High-resolution CSI reporting based on unequal bit allocation in advanced wireless communication systems

ABSTRACT

Methods and apparatuses for reporting a precoding matrix indicator (PMI). A user equipment (UE) includes a processor configured to generate a report for a PMI. The report includes (i) a wideband amplitude coefficient indicator that is common for a plurality of subbands configured for reporting and (ii) a subband amplitude coefficient indicator and a subband phase coefficient indicator for each of the subbands. The UE further includes a transceiver operably connected to the processor. The transceiver configured to transmit the generated report for the PMI to a base station.

CROSS-REFERENCE TO RELATED APPLICATIONS AND CLAIM OF PRIORITY

This application is a continuation of U.S. Non-Provisional patentapplication Ser. No. 15/947,539 filed Apr. 6, 2018, and claims priorityto: U.S. Provisional Patent Application No. 62/485,155 filed on Apr. 13,2017; U.S. Provisional Patent Application No. 62/487,263 filed on Apr.19, 2017; U.S. Provisional Patent Application No. 62/487,818 filed onApr. 20, 2017; U.S. Provisional Patent Application No. 62/488,383 filedon Apr. 21, 2017; and U.S. Provisional Patent Application Ser. No.62/545,218 filed on Aug. 14, 2017. The content of the above-identifiedpatent documents is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to CSI reporting schemes basedon an unequal bit allocation in advanced wireless communication systems.

BACKGROUND

Understanding and correctly estimating the channel in an advancewireless communication system between a user equipment (UE) and an eNodeB (eNB) is important for efficient and effective wireless communication.In order to correctly estimate the channel conditions, the UE may report(e.g., feedback) information about channel measurement, e.g., CSI, tothe eNB. With this information about the channel, the eNB is able toselect appropriate communication parameters to efficiently andeffectively perform wireless data communication with the UE. However,with increase in the numbers of antennas and channel paths of wirelesscommunication devices, so too has the amount of feedback increased thatmay be needed to ideally estimate the channel. This additionally-desiredchannel feedback may create additional overheads, thus reducing theefficiency of the wireless communication, for example, decrease the datarate.

SUMMARY

Embodiments of the present disclosure provide methods and apparatusesfor CSI reporting schemes based on an unequal bit allocation in anadvanced wireless communication system.

In one embodiment, a UE is provided. The UE includes a processorconfigured to generate a report for a precoding matrix indicator (PMI).The report includes (i) a wideband amplitude coefficient indicator thatis common for a plurality of subbands configured for reporting and (ii)a subband amplitude coefficient indicator and a subband phasecoefficient indicator for each of the subbands. The UE further includesa transceiver operably connected to the processor. The transceiver isconfigured to transmit the generated report for the PMI to a basestation.

In another embodiment, a base station (BS) is provided. The BS includesa transceiver configured to receive a report for a PMI. The reportincludes (i) a wideband amplitude coefficient indicator that is commonfor a plurality of subbands configured for reporting and (ii) a subbandamplitude coefficient indicator and a subband phase coefficientindicator for each of the subbands. The BS also includes a processoroperably connected to the transceiver.

In yet another embodiment, a method for reporting a PMI by a UE isprovided. The method includes generating a report for a PMI. The reportincludes (i) a wideband amplitude coefficient indicator that is commonfor a plurality of subbands configured for reporting and (ii) a subbandamplitude coefficient indicator and a subband phase coefficientindicator for each of the subbands. The method further includestransmitting the generated report for the PMI to a base station.

Other technical features may be readily apparent to one skilled in theart from the following figures, descriptions, and claims.

Before undertaking the DETAILED DESCRIPTION below, it may beadvantageous to set forth definitions of certain words and phrases usedthroughout this patent document. The term “couple” and its derivativesrefer to any direct or indirect communication between two or moreelements, whether or not those elements are in physical contact with oneanother. The terms “transmit,” “receive,” and “communicate,” as well asderivatives thereof, encompass both direct and indirect communication.The terms “include” and “comprise,” as well as derivatives thereof, meaninclusion without limitation. The term “or” is inclusive, meaningand/or. The phrase “associated with,” as well as derivatives thereof,means to include, be included within, interconnect with, contain, becontained within, connect to or with, couple to or with, be communicablewith, cooperate with, interleave, juxtapose, be proximate to, be boundto or with, have, have a property of, have a relationship to or with, orthe like. The term “controller” means any device, system or part thereofthat controls at least one operation. Such a controller may beimplemented in hardware or a combination of hardware and software and/orfirmware. The functionality associated with any particular controllermay be centralized or distributed, whether locally or remotely. Thephrase “at least one of,” when used with a list of items, means thatdifferent combinations of one or more of the listed items may be used,and only one item in the list may be needed. For example, “at least oneof: A, B, and C” includes any of the following combinations: A, B, C, Aand B, A and C, B and C, and A and B and C.

Moreover, various functions described below can be implemented orsupported by one or more computer programs, each of which is formed fromcomputer readable program code and embodied in a computer readablemedium. The terms “application” and “program” refer to one or morecomputer programs, software components, sets of instructions,procedures, functions, objects, classes, instances, related data, or aportion thereof adapted for implementation in a suitable computerreadable program code. The phrase “computer readable program code”includes any type of computer code, including source code, object code,and executable code. The phrase “computer readable medium” includes anytype of medium capable of being accessed by a computer, such as readonly memory (ROM), random access memory (RAM), a hard disk drive, acompact disc (CD), a digital video disc (DVD), or any other type ofmemory. A “non-transitory” computer readable medium excludes wired,wireless, optical, or other communication links that transporttransitory electrical or other signals. A non-transitory computerreadable medium includes media where data can be permanently stored andmedia where data can be stored and later overwritten, such as arewritable optical disc or an erasable memory device.

Definitions for other certain words and phrases are provided throughoutthis patent document. Those of ordinary skill in the art shouldunderstand that in many if not most instances, such definitions apply toprior as well as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following description taken inconjunction with the accompanying drawings, in which like referencenumerals represent like parts:

FIG. 1 illustrates an example wireless network according to embodimentsof the present disclosure;

FIG. 2 illustrates an example eNB according to embodiments of thepresent disclosure;

FIG. 3 illustrates an example UE according to embodiments of the presentdisclosure;

FIG. 4A illustrates a high-level diagram of an orthogonal frequencydivision multiple access transmit path according to embodiments of thepresent disclosure;

FIG. 4B illustrates a high-level diagram of an orthogonal frequencydivision multiple access receive path according to embodiments of thepresent disclosure;

FIG. 5 illustrates a transmitter block diagram for a PDSCH in a subframeaccording to embodiments of the present disclosure;

FIG. 6 illustrates a receiver block diagram for a PDSCH in a subframeaccording to embodiments of the present disclosure;

FIG. 7 illustrates a transmitter block diagram for a PUSCH in a subframeaccording to embodiments of the present disclosure;

FIG. 8 illustrates a receiver block diagram for a PUSCH in a subframeaccording to embodiments of the present disclosure;

FIG. 9 illustrates an example multiplexing of two slices according toembodiments of the present disclosure;

FIG. 10 illustrates an example antenna blocks according to embodimentsof the present disclosure;

FIG. 11 illustrates an example network configuration according toembodiments of the present disclosure;

FIG. 12 illustrates an example 2D antenna port layout according toembodiments of the present disclosure; and

FIG. 13 illustrates a flowchart of a method for PMI reporting accordingto embodiments of the present disclosure.

DETAILED DESCRIPTION

FIG. 1 through FIG. 13, discussed below, and the various embodimentsused to describe the principles of the present disclosure in this patentdocument are by way of illustration only and should not be construed inany way to limit the scope of the disclosure. Those skilled in the artwill understand that the principles of the present disclosure may beimplemented in any suitably arranged system or device.

The following documents and standards descriptions are herebyincorporated by reference into the present disclosure as if fully setforth herein: 3GPP TS 36.211 v14.2.0, “E-UTRA, Physical channels andmodulation;” 3GPP TS 36.212 v14.2.0, “E-UTRA, Multiplexing and Channelcoding;” 3GPP TS 36.213 v14.2.0, “E-UTRA, Physical Layer Procedures;”3GPP TS 36.321 v14.2.0, “E-UTRA, Medium Access Control (MAC) protocolspecification;” 3GPP TS 36.331 v14.2.0, “E-UTRA, Radio Resource Control(RRC) protocol specification” and 3GPP TR 22.891 v1.2.0, “FeasibilityStudy on New Services and Markets Technology Enablers.”

Aspects, features, and advantages of the disclosure are readily apparentfrom the following detailed description, simply by illustrating a numberof particular embodiments and implementations, including the best modecontemplated for carrying out the disclosure. The disclosure is alsocapable of other and different embodiments, and its several details canbe modified in various obvious respects, all without departing from thespirit and scope of the disclosure. Accordingly, the drawings anddescription are to be regarded as illustrative in nature, and not asrestrictive. The disclosure is illustrated by way of example, and not byway of limitation, in the figures of the accompanying drawings.

In the following, for brevity, both FDD and TDD are considered as theduplex method for both DL and UL signaling.

Although exemplary descriptions and embodiments to follow assumeorthogonal frequency division multiplexing (OFDM) or orthogonalfrequency division multiple access (OFDMA), this disclosure can beextended to other OFDM-based transmission waveforms or multiple accessschemes such as filtered OFDM (F-OFDM).

The present disclosure covers several components which can be used inconjunction or in combination with one another, or can operate asstandalone schemes.

To meet the demand for wireless data traffic having increased sincedeployment of 4G communication systems, efforts have been made todevelop an improved 5G or pre-5G communication system. Therefore, the 5Gor pre-5G communication system is also called a “beyond 4G network” or a“post LTE system.”

The 5G communication system is considered to be implemented in higherfrequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higherdata rates. To decrease propagation loss of the radio waves and increasethe transmission coverage, the beamforming, massive multiple-inputmultiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna,an analog beam forming, large scale antenna techniques and the like arediscussed in 5G communication systems.

In addition, in 5G communication systems, development for system networkimprovement is under way based on advanced small cells, cloud radioaccess networks (RANs), ultra-dense networks, device-to-device (D2D)communication, wireless backhaul communication, moving network,cooperative communication, coordinated multi-points (CoMP) transmissionand reception, interference mitigation and cancellation and the like.

In the 5G system, hybrid frequency shift keying and quadrature amplitudemodulation (FQAM) and sliding window superposition coding (SWSC) as anadaptive modulation and coding (AMC) technique, and filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse codemultiple access (SCMA) as an advanced access technology have beendeveloped.

FIGS. 1-4B below describe various embodiments implemented in wirelesscommunications systems and with the use of orthogonal frequency divisionmultiplexing (OFDM) or orthogonal frequency division multiple access(OFDMA) communication techniques. The descriptions of FIGS. 1-3 are notmeant to imply physical or architectural limitations to the manner inwhich different embodiments may be implemented. Different embodiments ofthe present disclosure may be implemented in any suitably-arrangedcommunications system.

FIG. 1 illustrates an example wireless network according to embodimentsof the present disclosure. The embodiment of the wireless network shownin FIG. 1 is for illustration only. Other embodiments of the wirelessnetwork 100 could be used without departing from the scope of thisdisclosure.

As shown in FIG. 1, the wireless network includes an eNB 101, an eNB102, and an eNB 103. The eNB 101 communicates with the eNB 102 and theeNB 103. The eNB 101 also communicates with at least one network 130,such as the Internet, a proprietary Internet Protocol (IP) network, orother data network.

The eNB 102 provides wireless broadband access to the network 130 for afirst plurality of user equipments (UEs) within a coverage area 120 ofthe eNB 102. The first plurality of UEs includes a UE 111, which may belocated in a small business (SB); a UE 112, which may be located in anenterprise (E); a UE 113, which may be located in a WiFi hotspot (HS); aUE 114, which may be located in a first residence (R); a UE 115, whichmay be located in a second residence (R); and a UE 116, which may be amobile device (M), such as a cell phone, a wireless laptop, a wirelessPDA, or the like. The eNB 103 provides wireless broadband access to thenetwork 130 for a second plurality of UEs within a coverage area 125 ofthe eNB 103. The second plurality of UEs includes the UE 115 and the UE116. In some embodiments, one or more of the eNBs 101-103 maycommunicate with each other and with the UEs 111-116 using 5G, LTE,LTE-A, WiMAX, WiFi, or other wireless communication techniques.

Depending on the network type, the term “base station” or “BS” can referto any component (or collection of components) configured to providewireless access to a network, such as transmit point (TP),transmit-receive point (TRP), an enhanced base station (eNodeB or eNB),a 5G base station (gNB), a macrocell, a femtocell, a WiFi access point(AP), or other wirelessly enabled devices. Base stations may providewireless access in accordance with one or more wireless communicationprotocols, e.g., 5G 3GPP new radio interface/access (NR), long termevolution (LTE), LTE advanced (LTE-A), high speed packet access (HSPA),Wi-Fi 802.11a/b/g/n/ac, etc. For the sake of convenience, the terms “BS”and “TRP” are used interchangeably in this patent document to refer tonetwork infrastructure components that provide wireless access to remoteterminals. Also, depending on the network type, the term “userequipment” or “UE” can refer to any component such as “mobile station,”“subscriber station,” “remote terminal,” “wireless terminal,” “receivepoint,” or “user device.” For the sake of convenience, the terms “userequipment” and “UE” are used in this patent document to refer to remotewireless equipment that wirelessly accesses a BS, whether the UE is amobile device (such as a mobile telephone or smartphone) or is normallyconsidered a stationary device (such as a desktop computer or vendingmachine).

Dotted lines show the approximate extents of the coverage areas 120 and125, which are shown as approximately circular for the purposes ofillustration and explanation only. It should be clearly understood thatthe coverage areas associated with eNBs, such as the coverage areas 120and 125, may have other shapes, including irregular shapes, dependingupon the configuration of the eNBs and variations in the radioenvironment associated with natural and man-made obstructions.

As described in more detail below, one or more of the UEs 111-116include circuitry, programing, or a combination thereof, for efficientCSI reporting in an advanced wireless communication system. In certainembodiments, and one or more of the eNBs 101-103 includes circuitry,programing, or a combination thereof, for receiving efficient CSIreporting for a PMI based on unequal bit allocation in an advancedwireless communication system.

Although FIG. 1 illustrates one example of a wireless network, variouschanges may be made to FIG. 1. For example, the wireless network couldinclude any number of eNBs and any number of UEs in any suitablearrangement. Also, the eNB 101 could communicate directly with anynumber of UEs and provide those UEs with wireless broadband access tothe network 130. Similarly, each eNB 102-103 could communicate directlywith the network 130 and provide UEs with direct wireless broadbandaccess to the network 130. Further, the eNBs 101, 102, and/or 103 couldprovide access to other or additional external networks, such asexternal telephone networks or other types of data networks.

FIG. 2 illustrates an example eNB 102 according to embodiments of thepresent disclosure. The embodiment of the eNB 102 illustrated in FIG. 2is for illustration only, and the eNBs 101 and 103 of FIG. 1 could havethe same or similar configuration. However, eNBs come in a wide varietyof configurations, and FIG. 2 does not limit the scope of thisdisclosure to any particular implementation of an eNB.

As shown in FIG. 2, the eNB 102 includes multiple antennas 205 a-205 n,multiple RF transceivers 210 a-210 n, transmit (TX) processing circuitry215, and receive (RX) processing circuitry 220. The eNB 102 alsoincludes a controller/processor 225, a memory 230, and a backhaul ornetwork interface 235.

The RF transceivers 210 a-210 n receive, from the antennas 205 a-205 n,incoming RF signals, such as signals transmitted by UEs in the network100. The RF transceivers 210 a-210 n down-convert the incoming RFsignals to generate IF or baseband signals. The IF or baseband signalsare sent to the RX processing circuitry 220, which generates processedbaseband signals by filtering, decoding, and/or digitizing the basebandor IF signals. The RX processing circuitry 220 transmits the processedbaseband signals to the controller/processor 225 for further processing.

The TX processing circuitry 215 receives analog or digital data (such asvoice data, web data, e-mail, or interactive video game data) from thecontroller/processor 225. The TX processing circuitry 215 encodes,multiplexes, and/or digitizes the outgoing baseband data to generateprocessed baseband or IF signals. The RF transceivers 210 a-210 nreceive the outgoing processed baseband or IF signals from the TXprocessing circuitry 215 and up-converts the baseband or IF signals toRF signals that are transmitted via the antennas 205 a-205 n.

The controller/processor 225 can include one or more processors or otherprocessing devices that control the overall operation of the eNB 102.For example, the controller/processor 225 could control the reception offorward channel signals and the transmission of reverse channel signalsby the RF transceivers 210 a-210 n, the RX processing circuitry 220, andthe TX processing circuitry 215 in accordance with well-knownprinciples. The controller/processor 225 could support additionalfunctions as well, such as more advanced wireless communicationfunctions.

For instance, the controller/processor 225 could support beam forming ordirectional routing operations in which outgoing signals from multipleantennas 205 a-205 n are weighted differently to effectively steer theoutgoing signals in a desired direction. Any of a wide variety of otherfunctions could be supported in the eNB 102 by the controller/processor225.

The controller/processor 225 is also capable of executing programs andother processes resident in the memory 230, such as an OS. Thecontroller/processor 225 can move data into or out of the memory 230 asrequired by an executing process.

The controller/processor 225 is also coupled to the backhaul or networkinterface 235. The backhaul or network interface 235 allows the eNB 102to communicate with other devices or systems over a backhaul connectionor over a network. The interface 235 could support communications overany suitable wired or wireless connection(s). For example, when the eNB102 is implemented as part of a cellular communication system (such asone supporting 5G, LTE, or LTE-A), the interface 235 could allow the eNB102 to communicate with other eNBs over a wired or wireless backhaulconnection. When the eNB 102 is implemented as an access point, theinterface 235 could allow the eNB 102 to communicate over a wired orwireless local area network or over a wired or wireless connection to alarger network (such as the Internet). The interface 235 includes anysuitable structure supporting communications over a wired or wirelessconnection, such as an Ethernet or RF transceiver.

The memory 230 is coupled to the controller/processor 225. Part of thememory 230 could include a RAM, and another part of the memory 230 couldinclude a Flash memory or other ROM.

Although FIG. 2 illustrates one example of eNB 102, various changes maybe made to FIG. 2. For example, the eNB 102 could include any number ofeach component shown in FIG. 2. As a particular example, an access pointcould include a number of interfaces 235, and the controller/processor225 could support routing functions to route data between differentnetwork addresses. As another particular example, while shown asincluding a single instance of TX processing circuitry 215 and a singleinstance of RX processing circuitry 220, the eNB 102 could includemultiple instances of each (such as one per RF transceiver). Also,various components in FIG. 2 could be combined, further subdivided, oromitted and additional components could be added according to particularneeds.

FIG. 3 illustrates an example UE 116 according to embodiments of thepresent disclosure. The embodiment of the UE 116 illustrated in FIG. 3is for illustration only, and the UEs 111-115 of FIG. 1 could have thesame or similar configuration. However, UEs come in a wide variety ofconfigurations, and FIG. 3 does not limit the scope of this disclosureto any particular implementation of a UE.

As shown in FIG. 3, the UE 116 includes an antenna 305, a radiofrequency (RF) transceiver 310, TX processing circuitry 315, amicrophone 320, and receive (RX) processing circuitry 325. The UE 116also includes a speaker 330, a processor 340, an input/output (I/O)interface (IF) 345, a touchscreen 350, a display 355, and a memory 360.The memory 360 includes an operating system (OS) 361 and one or moreapplications 362.

The RF transceiver 310 receives, from the antenna 305, an incoming RFsignal transmitted by an eNB of the network 100. The RF transceiver 310down-converts the incoming RF signal to generate an intermediatefrequency (IF) or baseband signal. The IF or baseband signal is sent tothe RX processing circuitry 325, which generates a processed basebandsignal by filtering, decoding, and/or digitizing the baseband or IFsignal. The RX processing circuitry 325 transmits the processed basebandsignal to the speaker 330 (such as for voice data) or to the processor340 for further processing (such as for web browsing data).

The TX processing circuitry 315 receives analog or digital voice datafrom the microphone 320 or other outgoing baseband data (such as webdata, e-mail, or interactive video game data) from the processor 340.The TX processing circuitry 315 encodes, multiplexes, and/or digitizesthe outgoing baseband data to generate a processed baseband or IFsignal. The RF transceiver 310 receives the outgoing processed basebandor IF signal from the TX processing circuitry 315 and up-converts thebaseband or IF signal to an RF signal that is transmitted via theantenna 305.

The processor 340 can include one or more processors or other processingdevices and execute the OS 361 stored in the memory 360 in order tocontrol the overall operation of the UE 116. For example, the processor340 could control the reception of forward channel signals and thetransmission of reverse channel signals by the RF transceiver 310, theRX processing circuitry 325, and the TX processing circuitry 315 inaccordance with well-known principles. In some embodiments, theprocessor 340 includes at least one microprocessor or microcontroller.

The processor 340 is also capable of executing other processes andprograms resident in the memory 360, such as processes for CSI reportingfor a PMI based on unequal bit allocation. The processor 340 can movedata into or out of the memory 360 as required by an executing process.In some embodiments, the processor 340 is configured to execute theapplications 362 based on the OS 361 or in response to signals receivedfrom eNBs or an operator. The processor 340 is also coupled to the I/Ointerface 345, which provides the UE 116 with the ability to connect toother devices, such as laptop computers and handheld computers. The I/Ointerface 345 is the communication path between these accessories andthe processor 340.

The processor 340 is also coupled to the touchscreen 350 and the display355. The operator of the UE 116 can use the touchscreen 350 to enterdata into the UE 116. The display 355 may be a liquid crystal display,light emitting diode display, or other display capable of rendering textand/or at least limited graphics, such as from web sites.

The memory 360 is coupled to the processor 340. Part of the memory 360could include a random access memory (RAM), and another part of thememory 360 could include a Flash memory or other read-only memory (ROM).

Although FIG. 3 illustrates one example of UE 116, various changes maybe made to FIG. 3. For example, various components in FIG. 3 could becombined, further subdivided, or omitted and additional components couldbe added according to particular needs. As a particular example, theprocessor 340 could be divided into multiple processors, such as one ormore central processing units (CPUs) and one or more graphics processingunits (GPUs). Also, while FIG. 3 illustrates the UE 116 configured as amobile telephone or smartphone, UEs could be configured to operate asother types of mobile or stationary devices.

FIG. 4A is a high-level diagram of transmit path circuitry. For example,the transmit path circuitry may be used for an orthogonal frequencydivision multiple access (OFDMA) communication. FIG. 4B is a high-leveldiagram of receive path circuitry. For example, the receive pathcircuitry may be used for an orthogonal frequency division multipleaccess (OFDMA) communication. In FIGS. 4A and 4B, for downlinkcommunication, the transmit path circuitry may be implemented in a basestation (eNB) 102 or a relay station, and the receive path circuitry maybe implemented in a user equipment (e.g. user equipment 116 of FIG. 1).In other examples, for uplink communication, the receive path circuitry450 may be implemented in a base station (e.g. eNB 102 of FIG. 1) or arelay station, and the transmit path circuitry may be implemented in auser equipment (e.g. user equipment 116 of FIG. 1).

Transmit path circuitry comprises channel coding and modulation block405, serial-to-parallel (S-to-P) block 410, Size N Inverse Fast FourierTransform (IFFT) block 415, parallel-to-serial (P-to-S) block 420, addcyclic prefix block 425, and up-converter (UC) 430. Receive pathcircuitry 450 comprises down-converter (DC) 455, remove cyclic prefixblock 460, serial-to-parallel (S-to-P) block 465, Size N Fast FourierTransform (FFT) block 470, parallel-to-serial (P-to-S) block 475, andchannel decoding and demodulation block 480.

At least some of the components in FIGS. 4A 400 and 4B 450 may beimplemented in software, while other components may be implemented byconfigurable hardware or a mixture of software and configurablehardware. In particular, it is noted that the FFT blocks and the IFFTblocks described in this disclosure document may be implemented asconfigurable software algorithms, where the value of Size N may bemodified according to the implementation.

Furthermore, although this disclosure is directed to an embodiment thatimplements the Fast Fourier Transform and the Inverse Fast FourierTransform, this is by way of illustration only and may not be construedto limit the scope of the disclosure. It may be appreciated that in analternate embodiment of the present disclosure, the Fast FourierTransform functions and the Inverse Fast Fourier Transform functions mayeasily be replaced by discrete Fourier transform (DFT) functions andinverse discrete Fourier transform (IDFT) functions, respectively. Itmay be appreciated that for DFT and IDFT functions, the value of the Nvariable may be any integer number (i.e., 1, 4, 3, 4, etc.), while forFFT and IFFT functions, the value of the N variable may be any integernumber that is a power of two (i.e., 1, 2, 4, 8, 16, etc.).

In transmit path circuitry 400, channel coding and modulation block 405receives a set of information bits, applies coding (e.g., LDPC coding)and modulates (e.g., quadrature phase shift keying (QPSK) or quadratureamplitude modulation (QAM)) the input bits to produce a sequence offrequency-domain modulation symbols. Serial-to-parallel block 410converts (i.e., de-multiplexes) the serial modulated symbols to paralleldata to produce N parallel symbol streams where N is the IFFT/FFT sizeused in BS 102 and UE 116. Size N IFFT block 415 then performs an IFFToperation on the N parallel symbol streams to produce time-domain outputsignals. Parallel-to-serial block 420 converts (i.e., multiplexes) theparallel time-domain output symbols from Size N IFFT block 415 toproduce a serial time-domain signal. Add cyclic prefix block 425 theninserts a cyclic prefix to the time-domain signal. Finally, up-converter430 modulates (i.e., up-converts) the output of add cyclic prefix block425 to RF frequency for transmission via a wireless channel. The signalmay also be filtered at baseband before conversion to RF frequency.

The transmitted RF signal arrives at UE 116 after passing through thewireless channel, and reverse operations to those at eNB 102 areperformed. Down-converter 455 down-converts the received signal tobaseband frequency, and remove cyclic prefix block 460 removes thecyclic prefix to produce the serial time-domain baseband signal.Serial-to-parallel block 465 converts the time-domain baseband signal toparallel time-domain signals. Size N FFT block 470 then performs an FFTalgorithm to produce N parallel frequency-domain signals.Parallel-to-serial block 475 converts the parallel frequency-domainsignals to a sequence of modulated data symbols. Channel decoding anddemodulation block 480 demodulates and then decodes the modulatedsymbols to recover the original input data stream.

Each of eNBs 101-103 may implement a transmit path that is analogous totransmitting in the downlink to user equipment 111-116 and may implementa receive path that is analogous to receiving in the uplink from userequipment 111-116. Similarly, each one of user equipment 111-116 mayimplement a transmit path corresponding to the architecture fortransmitting in the uplink to eNBs 101-103 and may implement a receivepath corresponding to the architecture for receiving in the downlinkfrom eNBs 101-103.

5G communication system use cases have been identified and described.Those use cases can be roughly categorized into three different groups.In one example, enhanced mobile broadband (eMBB) is determined to dowith high bits/sec requirement, with less stringent latency andreliability requirements. In another example, ultra reliable and lowlatency (URLL) is determined with less stringent bits/sec requirement.In yet another example, massive machine type communication (mMTC) isdetermined that a number of devices can be as many as 100,000 to 1million per km2, but the reliability/throughput/latency requirementcould be less stringent. This scenario may also involve power efficiencyrequirement as well, in that the battery consumption may be minimized aspossible.

A communication system includes a downlink (DL) that conveys signalsfrom transmission points such as BSs or NodeBs to UEs and an Uplink (UL)that conveys signals from UEs to reception points such as NodeBs. A UE,also commonly referred to as a terminal or a mobile station, may befixed or mobile and may be a cellular phone, a personal computer device,or an automated device. An eNodeB, which is generally a fixed station,may also be referred to as an access point or other equivalentterminology. For LTE systems, a NodeB is often referred as an eNodeB.

In a communication system, such as LTE system, DL signals can includedata signals conveying information content, control signals conveying DLcontrol information (DCI), and reference signals (RS) that are alsoknown as pilot signals. An eNodeB transmits data information through aphysical DL shared channel (PDSCH). An eNodeB transmits DCI through aphysical DL control channel (PDCCH) or an Enhanced PDCCH (EPDCCH).

An eNodeB transmits acknowledgement information in response to datatransport block (TB) transmission from a UE in a physical hybrid ARQindicator channel (PHICH). An eNodeB transmits one or more of multipletypes of RS including a UE-common RS (CRS), a channel state informationRS (CSI-RS), or a demodulation RS (DMRS). A CRS is transmitted over a DLsystem bandwidth (BW) and can be used by UEs to obtain a channelestimate to demodulate data or control information or to performmeasurements. To reduce CRS overhead, an eNodeB may transmit a CSI-RSwith a smaller density in the time and/or frequency domain than a CRS.DMRS can be transmitted only in the BW of a respective PDSCH or EPDCCHand a UE can use the DMRS to demodulate data or control information in aPDSCH or an EPDCCH, respectively. A transmission time interval for DLchannels is referred to as a subframe and can have, for example,duration of 1 millisecond.

DL signals also include transmission of a logical channel that carriessystem control information. A BCCH is mapped to either a transportchannel referred to as a broadcast channel (BCH) when the DL signalsconvey a master information block (MIB) or to a DL shared channel(DL-SCH) when the DL signals convey a System Information Block (SIB).Most system information is included in different SIBs that aretransmitted using DL-SCH. A presence of system information on a DL-SCHin a subframe can be indicated by a transmission of a correspondingPDCCH conveying a codeword with a cyclic redundancy check (CRC)scrambled with system information RNTI (SI-RNTI). Alternatively,scheduling information for a SIB transmission can be provided in anearlier SIB and scheduling information for the first SIB (SIB-1) can beprovided by the MIB.

DL resource allocation is performed in a unit of subframe and a group ofphysical resource blocks (PRBs). A transmission BW includes frequencyresource units referred to as resource blocks (RBs). Each RB includesN_(sc) ^(RB) sub-carriers, or resource elements (REs), such as 12 REs. Aunit of one RB over one subframe is referred to as a PRB. A UE can beallocated M_(PDSCH) RBs for a total of M_(sc) ^(PDSCH)=M_(PDSCH)·N_(sc)^(RB) REs for the PDSCH transmission BW.

UL signals can include data signals conveying data information, controlsignals conveying UL control information (UCI), and UL RS. UL RSincludes DMRS and Sounding RS (SRS). A UE transmits DMRS only in a BW ofa respective PUSCH or PUCCH. An eNodeB can use a DMRS to demodulate datasignals or UCI signals. A UE transmits SRS to provide an eNodeB with anUL CSI. A UE transmits data information or UCI through a respectivephysical UL shared channel (PUSCH) or a Physical UL control channel(PUCCH). If a UE needs to transmit data information and UCI in a same ULsubframe, the UE may multiplex both in a PUSCH. UCI includes HybridAutomatic Repeat request acknowledgement (HARQ-ACK) information,indicating correct (ACK) or incorrect (NACK) detection for a data TB ina PDSCH or absence of a PDCCH detection (DTX), scheduling request (SR)indicating whether a UE has data in the UE's buffer, rank indicator(RI), and channel state information (CSI) enabling an eNodeB to performlink adaptation for PDSCH transmissions to a UE. HARQ-ACK information isalso transmitted by a UE in response to a detection of a PDCCH/EPDCCHindicating a release of semi-persistently scheduled PDSCH.

An UL subframe includes two slots. Each slot includes N_(symb) ^(UL)symbols for transmitting data information, UCI, DMRS, or SRS. Afrequency resource unit of an UL system BW is a RB. A UE is allocatedN_(RB) RBs for a total of N_(RB)·N_(sc) ^(RB) REs for a transmission BW.For a PUCCH, N_(RB)=1. A last subframe symbol can be used to multiplexSRS transmissions from one or more UEs. A number of subframe symbolsthat are available for data/UCI/DMRS transmission isN_(symb)=2·(N_(symb) ^(UL)−1)−N_(SRS), where N_(SRS)=1 if a lastsubframe symbol is used to transmit SRS and N_(SRS)=0 otherwise.

FIG. 5 illustrates a transmitter block diagram 500 for a PDSCH in asubframe according to embodiments of the present disclosure. Theembodiment of the transmitter block diagram 500 illustrated in FIG. 5 isfor illustration only. FIG. 5 does not limit the scope of thisdisclosure to any particular implementation of the transmitter blockdiagram 500.

As shown in FIG. 5, information bits 510 are encoded by encoder 520,such as a turbo encoder, and modulated by modulator 530, for exampleusing quadrature phase shift keying (QPSK) modulation. A serial toparallel (S/P) converter 540 generates M modulation symbols that aresubsequently provided to a mapper 550 to be mapped to REs selected by atransmission BW selection unit 555 for an assigned PDSCH transmissionBW, unit 560 applies an Inverse fast Fourier transform (IFFT), theoutput is then serialized by a parallel to serial (P/S) converter 570 tocreate a time domain signal, filtering is applied by filter 580, and asignal transmitted 590. Additional functionalities, such as datascrambling, cyclic prefix insertion, time windowing, interleaving, andothers are well known in the art and are not shown for brevity.

FIG. 6 illustrates a receiver block diagram 600 for a PDSCH in asubframe according to embodiments of the present disclosure. Theembodiment of the diagram 600 illustrated in FIG. 6 is for illustrationonly. FIG. 6 does not limit the scope of this disclosure to anyparticular implementation of the diagram 600.

As shown in FIG. 6, a received signal 610 is filtered by filter 620, REs630 for an assigned reception BW are selected by BW selector 635, unit640 applies a fast Fourier transform (FFT), and an output is serializedby a parallel-to-serial converter 650. Subsequently, a demodulator 660coherently demodulates data symbols by applying a channel estimateobtained from a DMRS or a CRS (not shown), and a decoder 670, such as aturbo decoder, decodes the demodulated data to provide an estimate ofthe information data bits 680. Additional functionalities such astime-windowing, cyclic prefix removal, de-scrambling, channelestimation, and de-interleaving are not shown for brevity.

FIG. 7 illustrates a transmitter block diagram 700 for a PUSCH in asubframe according to embodiments of the present disclosure. Theembodiment of the block diagram 700 illustrated in FIG. 7 is forillustration only. FIG. 7 does not limit the scope of this disclosure toany particular implementation of the block diagram 700.

As shown in FIG. 7, information data bits 710 are encoded by encoder720, such as a turbo encoder, and modulated by modulator 730. A discreteFourier transform (DFT) unit 740 applies a DFT on the modulated databits, REs 750 corresponding to an assigned PUSCH transmission BW areselected by transmission BW selection unit 755, unit 760 applies an IFFTand, after a cyclic prefix insertion (not shown), filtering is appliedby filter 770 and a signal transmitted 780.

FIG. 8 illustrates a receiver block diagram 800 for a PUSCH in asubframe according to embodiments of the present disclosure. Theembodiment of the block diagram 800 illustrated in FIG. 8 is forillustration only. FIG. 8 does not limit the scope of this disclosure toany particular implementation of the block diagram 800.

As shown in FIG. 8, a received signal 810 is filtered by filter 820.Subsequently, after a cyclic prefix is removed (not shown), unit 830applies a FFT, REs 840 corresponding to an assigned PUSCH reception BWare selected by a reception BW selector 845, unit 850 applies an inverseDFT (IDFT), a demodulator 860 coherently demodulates data symbols byapplying a channel estimate obtained from a DMRS (not shown), a decoder870, such as a turbo decoder, decodes the demodulated data to provide anestimate of the information data bits 880.

In next generation cellular systems, various use cases are envisionedbeyond the capabilities of LTE system. Termed 5G or the fifth generationcellular system, a system capable of operating at sub-6 GHz and above-6GHz (for example, in mmWave regime) becomes one of the requirements. In3GPP TR 22.891, 74 5G use cases has been identified and described; thoseuse cases can be roughly categorized into three different groups. Afirst group is termed ‘enhanced mobile broadband’ (eMBB), targeted tohigh data rate services with less stringent latency and reliabilityrequirements. A second group is termed “ultra-reliable and low latency(URLL)” targeted for applications with less stringent data raterequirements, but less tolerant to latency. A third group is termed“massive MTC (mMTC)” targeted for large number of low-power deviceconnections such as 1 million per km² with less stringent thereliability, data rate, and latency requirements.

In order for the 5G network to support such diverse services withdifferent quality of services (QoS), one method has been identified inLTE specification, called network slicing. To utilize PHY resourcesefficiently and multiplex various slices (with different resourceallocation schemes, numerologies, and scheduling strategies) in DL-SCH,a flexible and self-contained frame or subframe design is utilized.

FIG. 9 illustrates an example multiplexing of two slices 900 accordingto embodiments of the present disclosure. The embodiment of themultiplexing of two slices 900 illustrated in FIG. 9 is for illustrationonly. FIG. 9 does not limit the scope of this disclosure to anyparticular implementation of the multiplexing of two slices 900.

Two exemplary instances of multiplexing two slices within a commonsubframe or frame are depicted in FIG. 9. In these exemplaryembodiments, a slice can be composed of one or two transmissioninstances where one transmission instance includes a control (CTRL)component (e.g., 920 a, 960 a, 960 b, 920 b, or 960 c) and a datacomponent (e.g., 930 a, 970 a, 970 b, 930 b, or 970 c). In embodiment910, the two slices are multiplexed in frequency domain whereas inembodiment 950, the two slices are multiplexed in time domain. These twoslices can be transmitted with different sets of numerology.

LTE specification supports up to 32 CSI-RS antenna ports which enable aneNB to be equipped with a large number of antenna elements (such as 64or 128). In this case, a plurality of antenna elements is mapped ontoone CSI-RS port. For next generation cellular systems such as 5G, themaximum number of CSI-RS ports can either remain the same or increase.

FIG. 10 illustrates an example antenna blocks 1000 according toembodiments of the present disclosure. The embodiment of the antennablocks 1000 illustrated in FIG. 10 is for illustration only. FIG. 10does not limit the scope of this disclosure to any particularimplementation of the antenna blocks 1000.

For mmWave bands, although the number of antenna elements can be largerfor a given form factor, the number of CSI-RS ports—which can correspondto the number of digitally precoded ports—tends to be limited due tohardware constraints (such as the feasibility to install a large numberof ADCs/DACs at mmWave frequencies) as illustrated in FIG. 10. In thiscase, one CSI-RS port is mapped onto a large number of antenna elementswhich can be controlled by a bank of analog phase shifters. One CSI-RSport can then correspond to one sub-array which produces a narrow analogbeam through analog beamforming. This analog beam can be configured tosweep across a wider range of angles by varying the phase shifter bankacross symbols or subframes. The number of sub-arrays (equal to thenumber of RF chains) is the same as the number of CSI-RS portsN_(CSI-PORT). A digital beamforming unit performs a linear combinationacross N_(CSI-PORT) analog beams to further increase precoding gain.While analog beams are wideband (hence not frequency-selective), digitalprecoding can be varied across frequency sub-bands or resource blocks.

FIG. 11 illustrates an example network configuration 1100 according toembodiments of the present disclosure. The embodiment of the networkconfiguration 1100 illustrated in FIG. 11 is for illustration only. FIG.11 does not limit the scope of this disclosure to any particularimplementation of the block diagram 100.

In order for the 5G network to support such diverse services withdifferent quality of services (QoS), one scheme has been identified inLTE specification, called network slicing.

As shown in FIG. 11, An operator's network 1110 includes a number ofradio access network(s) 1120 (RAN(s)) that are associated with networkdevices such as eNBs 1130 a and 1130 b, small cell base stations(femto/pico eNBs or Wi-Fi access points) 1135 a and 1135 b. The network1110 can support various services, each represented as a slice.

In the example, an URLL slice 1140 a serves UEs requiring URLL servicessuch as cars 1145 b, trucks 1145 c, smart watches 1145 a, and smartglasses 1145 d. Two mMTC slices 1150 a and 550 b serve UEs requiringmMTC services such as power meters 555 b, and temperature control box1155 b. One eMBB slice 1160 a serves UEs requiring eMBB services such ascells phones 1165 a, laptops 1165 b, and tablets 1165 c. A deviceconfigured with two slices can also be envisioned.

From LTE specification, MIMO has been identified as an essential featurein order to achieve high system throughput requirements and it willcontinue to be the same in NR. One of the key components of a MIMOtransmission scheme is the accurate CSI acquisition at the eNB (or TRP).For MU-MIMO, in particular, the availability of accurate CSI isnecessary in order to guarantee high MU performance. For TDD systems,the CSI can be acquired using the SRS transmission relying on thechannel reciprocity.

For FDD systems, on the other hand, it can be acquired using the CSI-RStransmission from eNB, and CSI acquisition and feedback from UE. In FDDsystems, the CSI feedback framework is “implicit” in the form ofCQI/PMI/RI derived from a codebook assuming SU transmission from eNB.Because of the inherent SU assumption while deriving CSI, this implicitCSI feedback is inadequate for MU transmission. Since future (e.g. NR)systems are likely to be more MU-centric, this SU-MU CSI mismatch may bea bottleneck in achieving high MU performance gains. Another issue withimplicit feedback is the scalability with larger number of antenna portsat eNB.

For large number of antenna ports, the codebook design for implicitfeedback is quite complicated (for example, in LTE specification, thetotal number of Class A codebooks=44), and the designed codebook is notguaranteed to bring justifiable performance benefits in practicaldeployment scenarios (for example, only a small percentage gain can beshown at the most). Realizing aforementioned issues, it has agreed toprovide specification support to advanced CSI reporting in LTEspecification, which, at the very least, can serve as a good startingpoint to design advanced CSI scheme in NR MIMO. Compared to LTEspecification, the CSI acquisition for NR MIMO may consider thefollowing additional differentiating factors.

In one example of flexibility CSI reporting framework, CSI reporting inNR may be flexible to support users with different CSI reportingcapabilities. For example, some users may only be capable of reportingimplicit CSI in the form of PMI/CQI/RI as in LTE and some other usersmay be capable of reporting both implicit as well as explicit channelreporting. In addition, UE motilities in NR can range from 0 kmph to 500kmph. So, CSI reporting framework may be able to support such diverseuse cases and UE capabilities.

In one example of increased number of antenna ports, in NR MIMO, thenumber of antenna elements at the eNB can be up to 256, which means thatthe total number of antenna ports can be more than 32, which is themaximum number of antenna ports supported in LTE eFD-MIMO. Although thiscan be accommodated with partial-port CSI-RS mapping where each subsetconsists of at most 32 ports, the total number of ports across time canbe extended to a much larger number. As the number of ports increases,meaningful system gain can only be obtained in a MU-centric system.

In one example of increased throughput requirement, the systemthroughput requirements (e.g. for eMBB in NR) is several times more thanthat for LTE eFD-MIMO. Such high throughput requirements can only besatisfied by a mechanism to provide very accurate CSI to the eNB.

In one example of beamforming, following the trend established inFD-MIMO, NR MIMO system may be beam-formed either cell-specifically orUE-specifically, where the beams can either be of analog (RF) or digitalor hybrid type. For such a beam-formed system, a mechanism is needed toobtain accurate beam-forming information at the eNB.

In one example of unified design, since NR includes both above and below6 GHz frequency bands, a unified MIMO framework working for bothfrequency regimes may be preferable.

In the following, for brevity, both FDD and TDD are considered as theduplex method for both DL and UL signaling. Although exemplarydescriptions and embodiments to follow assume orthogonal frequencydivision multiplexing (OFDM) or orthogonal frequency division multipleaccess (OFDMA), the present disclosure can be extended to otherOFDM-based transmission waveforms or multiple access schemes such asfiltered OFDM (F-OFDM).

This disclosure of invention covers several components which can be usedin conjunction or in combination with one another, or can operate asstandalone schemes.

Depending on the network type, the term “base station” or “BS” can referto any component (or collection of components) configured to providewireless access to a network, such as transmit point (TP),transmit-receive point (TRP), an enhanced base station (eNodeB or eNB),gNB, a macrocell, a femtocell, a WiFi access point (AP), or otherwirelessly enabled devices. Base stations may provide wireless access inaccordance with one or more wireless communication protocols, e.g., 5G3GPP new radio interface/access (NR), long term evolution (LTE), LTEadvanced (LTE-A), high speed packet access (HSPA), Wi-Fi802.11a/b/g/n/ac, etc. For the sake of convenience, the terms “BS” and“TRP” are used interchangeably in this patent document to refer tonetwork infrastructure components that provide wireless access to remoteterminals.

Also, depending on the network type, the term “user equipment” or “UE”can refer to any component such as “mobile station,” “subscriberstation,” “remote terminal,” “wireless terminal,” “receive point,” or“user device.” For the sake of convenience, the terms “user equipment”and “UE” are used in this patent document to refer to remote wirelessequipment that wirelessly accesses a BS, whether the UE is a mobiledevice (such as a mobile telephone or smartphone) or is normallyconsidered a stationary device (such as a desktop computer or vendingmachine).

FIG. 12 illustrates an example 2D antenna port layout 1200 according toembodiments of the present disclosure. The embodiment of the 2D antennaport layout 1200 illustrated in FIG. 12 is for illustration only. FIG.12 does not limit the scope of this disclosure to any particularimplementation.

In the following, it is assumed that N₁ and N₂ are the number of antennaports with the same polarization in the first and second dimensions,respectively. For 2D antenna port layouts, it is determined that N₁>1,N₂>1, and for 1D antenna port layouts, it could have N₁>1 and N₂=1 orN₂>1 and N₁=1. In the rest of the disclosure, 1D antenna port layoutswith N₁>1 and N₂=1 is considered. The disclosure, however, is applicableto the other 1D port layouts with N₂>1 and N₁=1. For a dual-polarizedantenna port layout, the total number of antenna ports is 2N₁N₂.

In one embodiment, a dual-stage W=W₁W₂ codebook for high-resolution CSIreporting is provided. In such embodiment, W₁ codebook is used toselect: an orthogonal basis set comprising of uniformly spaced (L₁,L₂)DFT beams; L∈{2, 3, 4, 6, 8} beams freely out of the L₁L₂ DFT beams in abasis set; and/or per layer strongest beam out of L beams and twopolarizations. In such instance, L is either (e.g. RRC) configurable orUE reports a preferred L value. This selection is WB or partial band(e.g. a set of SBs). Two examples of basis set sizes are restrictedorthogonal basis set in which L₁L₂=min(8, N₁N₂) and full orthogonalbasis set in which L₁L₂=N₁N₂, one of the two is either supported in thespecification or configured via RRC signaling.

In such embodiment, W₂ codebook is used to combine L beams independentlyper layer with a common W₁ beam group, i.e., the selected L beams arethe same for all layers and two polarizations, but strongest beamselection is per layer. The amplitude and phase of the combiningcoefficients are reported separately where phase is reported per subband(SB) and amplitude is reported wideband (WB) or SB or both WB and SB.The number of SBs can be configured, and a WB report implies a reportthat is common for all SBs.

In one embodiment, a UE is configured with a high-resolution CSIcodebook in which the rank R pre-coding matrix is given by

$W = {\frac{1}{\sqrt{R}}\left\lbrack {W^{(0)}\mspace{14mu} W^{(1)}\mspace{14mu}\ldots\mspace{14mu} W^{({R - 1})}} \right\rbrack}$where the pre-coding vector for layer l is given by

${W^{(l)} = \frac{W_{1}^{(l)}W_{2}^{(l)}}{{W_{1}^{(l)}W_{2}^{(l)}}}},{{{where}:\mspace{14mu} W_{1}^{(l)}} = {\begin{bmatrix}B_{l} & 0 \\0 & B_{l}\end{bmatrix}P_{1,l}}}$if the strongest beam corresponds to one polarization, e.g. polarization0 (or +45);

$W_{1}^{(l)} = {\begin{bmatrix}0 & B_{l} \\B_{l} & 0\end{bmatrix}P_{1,l}}$if the strongest beam corresponds to other polarization, e.g.polarization 1 (or −45); and W₂ ^((l))=P_(2,l)c_(l).

The matrices B_(l), P_(1,l), P_(2,l), and vector c_(l) are defined asfollows. In one example, B_(l) is a N₁N₂×L basis matrix [b_(k) _(l,1)₍₀₎ _(,k) _(l,2) ₍₀₎ , . . . , b_(k) _(l,1) _((L−1)) _(,k) _(l,2)_((L−1)) ] common to both polarizations where b b_(k) _(l,1) ₍₀₎ _(,k)_(l,2) ₍₀₎ is one of the L orthogonal DFT beams selected from theselected (L₁,L₂) basis set, and {(k_(l,1) ^((i)),k_(l,2) ^((i))): i=0, 1. . . , L−1} are corresponding indices of L beams where (k_(l,1)⁽⁰⁾,k_(l,2) ⁽⁰⁾) is the strongest beam for layer l. Note that for rankR>1, the strongest beam can be different for different layers, hence theindex of the strongest beam is indicated per layer and this indicationis WB.

In one example, P_(1,l) is a 2L×2L diagonal matrix with diagonalelements [1 p_(1,l,1) . . . p_(1,l,L−1) p_(1,l,L) p_(1,l,L+1) . . .p_(1,l,2L−1)], each belonging to [0, 1], to indicate WB component of therelative beam power levels across L beams and two polarizations.

In one example, P_(2,l) is a 2L×2L diagonal matrix with diagonalelements [1 p_(2,l,1) . . . p_(2,l,L−1) p_(2,l,L) p_(2,l,L+1) . . .p_(2,l,2L−1)], each belonging to [0, 1], to indicate SB component of therelative beam power levels across L beams and two polarizations.

In one example, c_(l) is a 2L×1 vector [1 c_(l,1) . . . c_(l,L−1)c_(l,L) c_(l,L+1) . . . c_(l,2L−1)]^(T), where

$c_{l,i} = {\exp\left( \frac{j2\pi n}{2^{N}} \right)}$∀i; n∈{0, 1, . . . , 2^(N)−1}, N∈{2, 3, 4}, to indicate SB relativephase of coefficients across L beams and two polarizations.

Note that one of the diagonal elements of P_(1,l), P_(2,l), and elementsof c_(l) is exactly one which corresponds to the strongest beam whosecoefficient (both power and phase) can be assumed to be one in general.Also, if only WB components of relative beam power levels are reported,then P_(2,l) is an identity matrix (hence not reported). Likewise, ifonly SB components of relative beam power levels are reported, thenP_(1,l) is an identity matrix (hence not reported).

In the present disclosure, the bit allocation to report amplitudes orbeam power levels, p_(1,l,i) and p_(2,l,i), and relative phase c_(l,i),where 0≤i≤2L−1, are considered. In particular, the focus is on the casein which unequal number of bits are allocated to report p_(1,l,i),p_(2,l,i), and c_(l,i).

In the rest of the present disclosure, p_(1,l,i) and p_(2,l,i) arereferred to as amplitudes of beam combining coefficients or weights.They can also be referred to as beam power levels. Also, p_(1,l,i)p_(2,l,i), and c_(l,i) can equivalently be referred to as widebandamplitude coefficient, subband amplitude coefficient, and subband phasecoefficient, respectively. Likewise, p_(1,l,i) and p_(2,l,i) canequivalently be referred to as a first amplitude coefficient and asecond amplitude coefficient, respectively.

In some embodiment 0, a UE is configured with a high-resolution CSIcodebook W=W₁W₂ as explained above in which at least one of p_(2,l,i),and c_(l,j) are quantized as follows. In one example of Sorting, the 2Lcoefficients per layer are sorted in decreasing order. Let {tilde over(p)}_(1,l,i) and {tilde over (p)}_(2,l,i) denote amplitudes p_(1,l,i)and p_(2,l,i) after sorting, and {tilde over (c)}_(l,i) denote phasec_(l,i) after sorting. Note that since the coefficients can benormalized with the strongest coefficient (which corresponds to thelargest amplitude), the coefficients can be assumed that {tilde over(p)}_(1,l,0)=1, {tilde over (p)}_(2,l,0)=1, and {tilde over(c)}_(l,0)=1, hence the coefficients are not reported.

In one example of amplitude quantization, to report amplitude of thei-th sorted coefficient (where i>0), the ratio between i-th and (i−1)-thsorted amplitudes,

${r_{1,l,i} = \frac{{\overset{˜}{p}}_{1,l,i}}{{\overset{˜}{p}}_{1,l,{i - 1}}}},$is quantized, where i>0, where {circumflex over (r)}_(1,l,i) denotes thequantized ratio of sorted amplitudes. To reconstruct the i-th sortedamplitude, the multiplication {circumflex over (r)}_(1,l,i){circumflexover (r)}_(1,l,i−1) is considered, where {circumflex over(r)}_(1,l,i)=1. The quantized ratio {circumflex over (r)}_(2,l,i) for

$r_{2,l,i} = \frac{{\overset{˜}{p}}_{2,l,i}}{{\overset{˜}{p}}_{2,l,{i - 1}}}$can be defined similarly. Let N is the number of bits to quantize eachamplitude. The amplitude quantization codebook is either C₀ or C₁ whichare defined as follows: if N=0, then C₀=C₁={1}; if N=1, then C₀={1,√{square root over (0.5)}} and C₁={1,0}; if N=2, then C₀={1, √{squareroot over (0.5)}, √{square root over (0.25)}, √{square root over(0.125)}} and C₁={1, √{square root over (0.5)}, √{square root over(0.25)}, 0}; and if N=3, then C₀={1, √{square root over (0.5)}, √{squareroot over (0.25)}, √{square root over (0.125)}, √{square root over(0.0625)}, √{square root over (0.0313)}, √{square root over (0.0156)},√{square root over (0.0078)}} and C₁={1, √{square root over (0.5)},√{square root over (0.25)}, √{square root over (0.125)}, √{square rootover (0.0625)}, √{square root over (0.0313)}, √{square root over(0.0156)}, 0}.

In one example of phase quantization, to report phase of the i-th sortedcoefficient {tilde over (c)}_(l,i) (where i>0), 2^(K)-PSK alphabet isconsidered where K=0, 1, 2, 3.

The coefficient sorting information is reported either WB or SB. Thereporting can be fixed, for example to WB. Alternatively, the UE isconfigured with one of WB or SB reporting via 1-bit higher layer RRC ordynamic MAC CE or DCI based signaling.

When reported WB, the coefficient sorting information is reported eitherjointly with at least one WB CSI reports such as RI and WB beamselection, or separately as an independent WB CSI report. Similarly,when reported SB, the coefficient sorting information is reported eitherjointly with at least one SB CSI reports such as SB amplitude and SBphase, or separately as an independent SB CSI report.

Also, the coefficient sorting information is reported either common forall layers or independent per layer. In one scheme, one of the twosorting alternatives is fixed, for example to per layer sorting.Alternatively, the UE is configured with one of the two sortingalternatives via 1-bit higher layer RRC or dynamic MAC CE or DCI basedsignaling.

In some embodiments 1, a UE is configured with a high-resolution CSIcodebook in which amplitudes p_(1,l,i) and/or p_(2,l,i) for layer l andcoefficient i are quantized according to the aforementioned embodiments0. In addition, the amplitude sorting is WB according to at least one ofthe following alternatives. In one example of Alt 1-0, the amplitudesorting is common across two polarizations and common across all layers.For example, for 2-layer CSI reporting, the number of bits to report WBsorting information is ┌log₂(L!)┐, where L!=L×(L−1)× . . . ×2×1. ForL=4, this requires 5 bits. In another example of Alt 1-1, the amplitudesorting is common across two polarizations and independent across alllayers. For example, for 2-layer CSI reporting, the number of bits toreport WB sorting information is 2×┌log₂(L!)┐. For L=4, this requires 10bits.

In yet another example of Alt 1-2, the amplitude sorting is independentacross two polarizations and common across all layers. For example, for2-layer CSI reporting, the number of bits to report WB sortinginformation is ┌log₂((2L)!)┐, where (2L)!=2L×(2L−1)× . . . ×2×1. ForL=4, this requires 16 bits.

In yet another example of Alt 1-3, the amplitude sorting is independentacross two polarizations and independent across all layers. For example,for 2-layer CSI reporting, the number of bits to report WB sortinginformation is 2×┌log₂((2L)!)┐. For L=4, this requires 32 bits.

The amplitude sorting information is reported either jointly with atleast one WB CSI reports such as RI and WB beam selection, or separatelyas an independent WB CSI report.

For WB only amplitude (p_(1,l,i)) reporting or SB only amplitude(p_(2,l,i)) reporting, at least the following amplitude sorting methodscan be considered. In one method, only one of Alt 1-0 to Alt 1-3 issupported in the specification, e.g. Alt 1-0 or Alt 1-3. In anothermethod, only two of Alt 1-0 to Alt 1-3 are supported in thespecification, e.g. Alt 1-0 and Alt 1-3 or Alt 1-0 and Alt 1-2. In yetanother method, all of Alt 1-0 to Alt 1-3 is supported in thespecification. When multiple alternatives are supported, the UE iseither configured with one of them or UE reports a preferred alternativeas part the CSI report.

When both WB (p_(1,l,i)) and SB (p_(2,l,i)) amplitude are reported, theamplitude is either: common for both WB and SB amplitude componentsaccording to at least one of Alt 1-0 to Alt 1-3; or independent for WBand SB amplitude components according to at least one of Alt 1-0 to Alt1-3. Note that the sorting information reporting payload is doubled inthis case.

Note that there is no need to report the strongest beam as part of theWB report since the strongest beam is already included in the amplitudesorting information which is reported WB.

In sub-embodiment 1-0, the phase sorting follows amplitude sorting.

Let N_(1,l,i) and N_(2,l,i) respectively be the number of bits toquantize WB (r_(1,l,i)) and SB (r_(2,l,i)) amplitude ratio or WB(p_(1,l,i)) and SB (p_(2,l,i)) amplitude for layer l and coefficient ias explained in the aforementioned embodiments 0. It is worth notingthat the strongest amplitude, r_(1,l,i) or r_(2,l,0), can be assumed be1 and hence not reported, i.e. 0 bit is assigned to report them.

In some embodiment 2, 2 layer CSI reporting for simplicity may beassumed. The embodiment, however, is applicable to more than 2 layers.In such embodiments, the number of bits to quantize the remaining 2L−1amplitude ratios (for each layer) is according to at least one of thefollowing alternatives.

In one example of Alt 2-0, it is common for all amplitudes, regardlessof the sorting alternative, i.e., a single value for N_(1,l,i) (orN_(2,l,i)) is used for each layer l and coefficient i. The single valueis either fixed, e.g. to 3 bits, or configured via RRC signaling, or UEreports as part of the CSI report (WB report).

In another example of Alt 2-1, it is independent for all amplitudes,regardless of the sorting alternative. In one instance of Alt 1-0 ofamplitude sorting, L−1 values N_(1,l,1) . . . N_(1,l,L−1) (or N_(2,l,i),. . . N_(2,l,L−1)) respectively are used for both amplitude indices i=1,. . . , L−1, and indices i=L+1, . . . , 2L−1 and for all layers l. Inone instance of Alt 1-1 of amplitude sorting, for Layer 0, L−1 valuesN_(1,0,1), . . . N_(1,0,L−1) (or N_(2,0,1), . . . N_(2,0,L−1))respectively are used for both amplitude indices i=1, . . . , L−1, andindices i=L+1, . . . , 2L−1. In one instance of Alt 1-1 of amplitudesorting, for Layer 1, . . . , L−1 values N_(1,l,1), . . . N_(1,1,L−1)(or N_(2,1,i), . . . N_(2,1,L−1)) respectively are used for bothamplitude indices i=1, . . . , L−1, and indices i=L+1, . . . , 2L−1.

In one instance of Alt 1-2 of amplitude sorting, 2L−1 values N_(1,l,1),. . . N_(1,l,2L−1) (or N_(2,l,1), . . . N_(2,l,2L−1)) respectively areused for amplitude indices i=1, . . . , 2L−1, and for all layers l.

In one instance of Alt 1-3 of amplitude sorting, for Layer 0, 2L−1values N_(1,0,1), . . . N_(1,0,2L−1) (or N_(2,0,1), . . . N_(2,0,2L−1))respectively are used for amplitude indices i=1, . . . , 2L−1. In oneinstance of Alt 1-3 of amplitude sorting, for Layer 1, 2L−1 valuesN_(1,1,1), . . . N_(1,1,2L−1) (or N_(2,1,1), . . . N_(2,1,2L−1))respectively are used for amplitude indices i=1, . . . , 2L−1.

The values for N_(1,l,i) (or N_(2,l,i)) are either fixed, e.g. from {0,1, 2, 3} bits, or configured via RRC signalling, or UE reports as partof the CSI report (WB report).

In one example of Alt 2-2, amplitudes are partitioned into multipledisjoint sets and each set is assigned a single value for amplitudereporting bits independently. A few examples of two sets are as follows.In one instance of Ex 2-0, the number of sets is 2, where the first sethas L₁=┌M/2┘ or └M/2┘ amplitudes, and the second set has L₂=M−L₁amplitudes, where M=L or 2L depending on the amplitude sortingalternatives in the aforementioned embodiment 1.

In one instance of Ex 2-1, the number of sets is 2, where the first sethas L₁=L amplitudes that correspond to the stronger L out of 2Lcoefficients, and the second set has the remaining L₂=L amplitudes thatcorrespond to weaker L out of 2L coefficients, where amplitude sortingalternatives 1-2 and 1-3 in the aforementioned embodiments 1 have beenassumed.

In one instance of Ex 2-2, the number of sets is 2, where the first sethas all but the weakest amplitude (corresponds to the M-th amplitude),and the second set has the weakest amplitude (the M-th amplitude).

In one instance of Ex 2-3, the number of sets is 2, where the first sethas all but the strongest amplitude (corresponds to the 1^(st)amplitude), and the second set has the strongest amplitude (the 1^(st)amplitude).

In one instance of Ex 2-4, the number of sets is L corresponding to eachof L beams. In case of Alt 1-2 and 1-3, the number of bits for amplitudequantization is common for the two amplitudes corresponding to the samebeam.

In sub-embodiment 2-0, the bit allocation to quantize phase of 2L−1coefficients follows that to quantize amplitude according to at leastone of Alt 2-0 to Alt 2-3.

Unless stated otherwise, the rest of the present disclosure is about bitallocation alternatives and are applicable to both amplitude and phasequantization. For brevity, only amplitude is mentioned in the followingembodiments. Also, the bit allocation alternatives for N_(1,l,0), . . .N_(1,l,2L−1) is explained. The alternatives however are also applicablefor the bit allocation for N_(2,l,0), . . . N_(2,l,2L−1).

In some embodiments 3, amplitudes or/and phases are partitioned into twodisjoint sets according to Alt 2-2 in the aforementioned embodiments 2,where each set has equal number (L) of coefficients, and the followingbit allocation is used for N_(1,l,0), . . . N_(1,l,2L−1) (for WBamplitude), N_(2,l,0), . . . N_(2,l,2L−1) (for SB amplitude), andM_(l,0), . . . M_(l,2L−1) (for SB phase).

Note that the coefficient indices i=0, 1, . . . 2L−1 correspond to thesorted coefficients. In one example, for the first leading beam orcoefficient out of 2L beams or coefficients, (N_(1,l,0), N_(2,l,0),M_(l,0))=(0,0,0), i.e., the amplitude and phase of the leading beamcoefficient is not reported, and, e.g. the leading beam coefficient isset to 1, where “leading” can also refer to the coefficient with thelargest amplitude (also referred to as the strongest coefficient laterin the disclosure). In one example for wideband amplitude+subbandamplitude reporting: (N_(1,l,i), N_(2,l,i), M_(l,i))=(P,1,3) for thefirst L−1 (out of 2L beams or coefficients) stronger beams orcoefficients, i.e., i=1, . . . , L−1; (N_(1,l,i), N_(2,l,i),M_(l,i))=(P,0,2) for the remaining L (out of 2L beams or coefficients)weaker beams or coefficients, i.e., i=L, . . . , 2L−1; and/or P=2 or 3.

In one example for subband only amplitude reporting: N_(1,l,i)=0 for alli; (N_(2,l,i), M_(l,i))=(1,3) for the first L−1 (out of 2L beams orcoefficients) stronger beams or coefficients, i.e., i=1, . . . , L−1;and/or (N_(2,l,i), M_(l,i))=(1,2) for the remaining L (out of 2L beamsor coefficients) weaker beams or coefficients, i.e., i=L, . . . , 2L−1.

In one example for wideband only amplitude reporting: N_(2,l,i)=0 forall i; and/or (N_(1,l,i), M_(l,i))=(P, Q), where P, Q=2 or 3.

In sub-embodiment 3-0, the bit allocation in the aforementionedembodiments 3 is applicable for all L values.

In sub-embodiment 3-1, the bit allocation in the aforementionedembodiments 3 is applicable for all L>R, where R=2 or 3 for example. Inthis case for L≤R, equal bit allocation is used for all coefficientsi=1, . . . , 2L−1.

In some embodiments 3A, amplitudes or/and phases are partitioned intotwo disjoint sets according to Alt 2-2 in the aforementioned embodiments2, where each set has K number of coefficients, and the following bitallocation is used for N_(1,l,0), . . . N_(1,l,2L−1) (for WB amplitude),N_(2,l,0), . . . N_(2,l,2L−)1 (for SB amplitude), and M_(l,0), . . .M_(l,2L−1) (for SB phase). Note that the coefficient indices i=0, 1, . .. , 2L−1 correspond to the sorted coefficients.

In one example for the first leading beam or coefficient out of 2L beamsor coefficients, (N_(1,l,0), N_(2,l,0), M_(l,0))=(0,0,0).

In one example for wideband amplitude+subband amplitude reporting:(N_(1,l,i), N_(2,l,i), M_(l,i))=(P,1,3) for the first K−1 (out of 2Lbeams or coefficients) stronger beams or coefficients, i.e., i=1, . . ., K−1; (N_(1,l,i), N_(2,l,i), M_(l,i))=(P,0,2) for the remaining 2L−K(out of 2L beams or coefficients) weaker beams or coefficients, i.e.,i=K, . . . , 2L−1; and/or P=2 or 3.

In one example for subband only amplitude reporting: N_(1,l,i)=0 for alli; (N_(2,l,i), M_(l,i))=(1,3) for the first K−1 (out of 2L beams orcoefficients) stronger beams or coefficients, i.e., i=1, . . . , K−1;and/or (N_(2,l,i), M_(l,i))=(1,2) for the remaining 2L−K (out of 2Lbeams or coefficients) weaker beams or coefficients, i.e., i=K, . . . ,2L−1.

In one example for wideband only amplitude reporting: N_(2,l,i)=0 forall i; and/or (N_(1,l,i), M_(l,i))=(P, Q), where P,Q=2 or 3.

A few alternatives for K are as follows: Alt 3A-0: K=2 for all L; Alt3A-1: K=L for all L; Alt 3A-2: K=2L for L=2 and K=L for L>2; Alt 3A-3:K=2L for L<3 and K=L for L>3; Alt 3A-4: K=2L for L<4 and K=L for L>4,for example 6 or 8; Alt 3A-5: K is configured via higher layer (RRC)signaling; Alt 3A-6: K is configured via MAC CE based signaling; Alt3A-7: K is configured via DCI (DL-related or UL related) signaling; Alt3A-8: K value for WB only amplitude reporting is the same as that forWB+SB amplitude reporting and is according to one of Alt 3A-0 to Alt3A-7; Alt 3A-9: K value for WB only amplitude reporting is differentfrom that for WB+SB amplitude reporting, and two different K values oneeach for WB only amplitude reporting and WB+SB amplitude reporting areused according to one of Alt 3A-0 to Alt 3A-7; and Alt 3A-10: K isaccording to a combination of at least two of Alt 3A-0 through Alt 3A-9.

In some embodiments 3B, a UE is configured to report wideband amplitudewith or without subband amplitude via higher-layer RRC signaling,wherein the bit allocation for (wideband amplitude, subband amplitude,subband phase quantization) with (N_(1,l,i), N_(2,l,i), M_(l,i)) bits isas follows. In one example for the leading (strongest) coefficient(corresponds to i=0) out of 2L coefficients, (N_(1,l,0), N_(2,l,0),M_(l,0))=(0,0,0), and the leading (strongest) coefficient=1.

In one example for wideband+subband amplitude reporting: (N_(1,l,i),N_(2,l,i))=(3,1) and M_(l,i)∈{2,3} for the first K−1 leading (strongest)coefficients out of the remaining 2L−1 coefficients (excluding thestrongest coefficient), i.e., i=1, . . . , K−1; where one of the two Mvalues is configured via higher-layer RRC signaling; (N_(1,l,i),N_(2,l,i), M_(l,i))=(3,0,2) for the remaining 2L−K (out of 2L−1coefficients) weaker coefficients, i.e., i=K, . . . , 2L−1; and/or K=2,3, . . . 2L.

In one example for wideband-only amplitude, i.e. N_(2,l,i)=0:(N_(1,l,i), N_(2,l,i))=(3,0) and M_(l,i)∈{2,3}; where one of the two Mvalues is configured via higher-layer RRC signaling; and/or thestrongest coefficient out of 2L coefficients is reported per layer in aWB manner.

In some embodiments 3C, the supported values of L∈{2,3,4} and the valueof K in the aforementioned embodiment 3B is according to at least one ofthe following alternatives. In one example of Alt 3C-0, only one fixedvalue for each value of L; one of the following examples is fixed in thespecification: Example 3C-0: K=L for all L; Example 3C-1: K=2L for L=2,and K=L for L=3,4; Example 3C-2: K=2L for L=2,3, and K=L for L=4;Example 3C-3: K=L+1 for all L; Example 3C-4: K=2L for L=2, and K=L+1 forL=3,4; Example 3C-5: K=2L for L=2,3, and K=L+1 for L=4; Example 3C-6:K=2L for L=2, K=L for L=3, and K=L+1 for L=4; Example 3C-7: K=2L forL=2, K=L+1 for L=3, and K=L for L=4; Example 3C-8: K=L for L=2, K=L forL=3, and K=L+1 for L=4; Example 3C-9: K=L for L=2, K=L+1 for L=3, andK=L+1 for L=4; Example 3C-10: K=L for L=2, K=L+1 for L=3, and K=L forL4; Example 3C-11: K=L+2 for all L; Example 3C-12: K=2L for L=2, andK=L+2 for L=3, 4; Example 3C-13: K=2L for L=2,3, and K=L+2 for L=4;Example 3C-14: K=2L for L=2, K=L+1 for L=3, and K=L+2 for L=4, i.e.,K=4, 4, and 6, for L=2, 3, and 4, respectively; and Example 3C-14: K=2L,K=L+2 for L=3, and K=L+1 for L=4.

In one example of Alt 3C-1, multiple K values for some or all values ofL and one K value is either configured via RRC signaling or the UEreports a preferred K value as a WB report.

In some embodiments 3D, for wideband+subband amplitude quantization, oneof equal bit allocation or unequal bit allocation is used depending onthe K value in the aforementioned embodiments 3B and embodiments 3C.

In one example, if K=2L, then the equal bit allocation is used for bothamplitude and phase, and in this case the following amplitudequantization method is used: the leading (strongest) coefficient(corresponds to i=0) out of 2L coefficients is reported per layer in aWB manner (as a WB report). This requires ┌log₂(2L)┘ bits per layer. ForL=4, it is 3 bits for rank 1 and 6 bits for rank 2 CSI reporting; andthe amplitude quantization is independent for each of the remaining 2L−1coefficients (i.e., dependent quantization such as the differentialacross coefficients as proposed in the aforementioned embodiments 0 isnot used).

In one example, if K<2L, one of following amplitude quantizationalternatives is used. In one instance of Alt 3D-0, 2L coefficients arereported according to the descending order of the reported WB amplitudesindependently for each layer, where the grouping information is reportedimplicitly with the WB amplitude report. This requires ┌log₂((2L)!)┘bits per layer. For L=4, it is 16 bits for rank 1 and 32 bits for rank 2CSI reporting.

In one instance of Alt 3D-1, 2L coefficients are grouped in two, wheregrouping information is reported in a WB manner independently for eachlayer. In addition, the leading (strongest) coefficient (corresponds toi=0) is reported (WB report) implicitly or explicitly as the strongestcoefficient belonging to the first coefficient group. In such instance,the first group corresponds to K leading (strongest) coefficients out of2L coefficients. In such instance, the second group corresponds to theremaining coefficients.

For each layer, this requires ┌log₂(_(K) ^(2L))┐ bits to report thefirst group and ┌log₂ K┐ bits to report the leading (strongest)coefficient. Note there is no reporting needed for the second group. ForL=4 and K=5, it requires 6 bits to report the first group and 3 bits toreport the leading coefficient per layer, which is 9 bits in total forrank 1 and 18 bits for rank 2 CSI reporting, respectively.

In one instance of Alt 3D-2, 2L coefficients are grouped in three, wheregrouping information is reported in a WB manner independently for eachlayer. In such instance, the first group corresponds to the leading(strongest) coefficient (corresponds to i=0) out of 2L coefficients. Insuch instance, the second group corresponds to K−1 leading (strongest)coefficients out of the remaining 2L−1 coefficients (excluding thestrongest coefficient). In such instance, the third group corresponds tothe remaining coefficients.

For each layer, this requires ┌log₂(2L)┐ bits to report the leading(strongest) coefficient and ┌log₂(_(K-1) ^(2L−1))┐ bits to report thefirst group. Note there is no reporting needed for the second group. ForL=4 and K=5, it requires 3 bits to report the leading coefficient perlayer and 6 bits to report the first group, which is 9 bits in total forrank 1 and 18 bits for rank 2 CSI reporting, respectively.

In one example of Alt 3D-3, the leading (strongest) coefficient(corresponds to i=0) out of 2L coefficients is reported per layer in aWB manner (as a WB report). The first group (K−1 strongest coefficientsper layer that use a larger bit allocation) is then determined directlyfrom the reported WB amplitudes, without any explicit reporting, basedon a fixed rule. A few examples of a fixed rule are as follows.

In one instance of Ex 3D-0, the reported WB amplitudes for the remaining2L−1 coefficient are sorted in decreasing order, and the first K−1 ofthe sorted amplitudes form the first group and the remaining sortedamplitudes form the second group. If the WB amplitudes for twocoefficients are identical, then the WB amplitudes are sorted inincreasing order of coefficient index i, i.e., if a_(k) and a_(r) aretwo WB amplitudes for coefficient k, r∈{1, 2, . . . 2L−1}, then a_(k)and a_(r) are sorted as . . . , a_(k), a_(r), . . . if k<r and as . . ., a_(r), a_(k), . . . otherwise.

In one instance of Ex 3D-1, the reported WB amplitudes for the remaining2L−1 coefficient are sorted in decreasing order, and the first K−1 ofthe sorted amplitudes form the first group and the remaining sortedamplitudes form the second group. If the WB amplitudes for twocoefficients are identical, then the WB amplitudes are sorted indecreasing order of coefficient index i, i.e., if a_(k) and a_(r) aretwo WB amplitudes for coefficient k, r∈{1, 2, . . . 2L−1}, then a_(k)and a_(r) are sorted as . . . , a_(k), a_(r), . . . if k>r and as . . ., a_(r), a_(k), . . . otherwise

The amplitude quantization in this case (K<2L) is either dependent(i.e., differential as proposed in the aforementioned embodiments 0) orindependent for each of the remaining 2L−1 coefficients. One of the twoamplitude quantization methods may be used in the specification.

In some embodiments 3E, for both wideband only and wideband+subbandamplitude quantization (depending on RRC configuration, cf. theaforementioned embodiments 3B), amplitude quantization is independentfor each of the remaining 2L−1 coefficients and for each layer. Thecodebook for amplitude quantization is as follows.

In one example of WB amplitude codebook, C_(WB)={1, √{square root over(0.5)}, √{square root over (0.25)}, √{square root over (0.125)},√{square root over (0.0625)}, √{square root over (0.0313)}, √{squareroot over (0.0156)}, 0} which corresponds to ={0, −3, −6, −9, −12, −15,−18, −∞} dB. An example of WB amplitude codebook table is shown inTABLE 1. Two alternatives are shown for indexing, one in increasing andthe other in decreasing order of amplitudes, one of them may be fixed.

In one example of SB amplitude codebook, C_(SB)={1, √{square root over(0.5)}} for the first group (for which N_(2,l,i)=1), which correspondsto ={0, −3} dB, and C_(SB)={1} for the second group (for whichN_(2,l,i)=0, SB amplitude is not reported). An example of SB amplitudecodebook table is shown in TABLE 2.

Two alternatives are shown for indexing, one in increasing and the otherin decreasing order of amplitudes, one of them may be fixed. In avariation, there is no separate codebook for SB amplitude. The SBamplitude codebook corresponds to indices I_(A,WB)=6,7 (Alt 0) or 0,1(Alt 1) in the WB amplitude codebook TABLE 1.

TABLE 1 WB amplitude codebook table Index WB amplitude (p_(1,l,i))(I_(A,WB)) Alt 0 Alt 1 0 0 1 1 $\frac{1}{\sqrt{64}} = \sqrt{0.0156}$$\frac{1}{\sqrt{2}} = \sqrt{0.5}$ 2$\frac{1}{\sqrt{32}} = \sqrt{0.0313}$ $\frac{1}{\sqrt{4}} = \sqrt{0.25}$3 $\frac{1}{\sqrt{16}} = \sqrt{0.0625}$$\frac{1}{\sqrt{8}} = \sqrt{0.125}$ 4$\frac{1}{\sqrt{8}} = \sqrt{0.125}$$\frac{1}{\sqrt{16}} = \sqrt{0.0625}$ 5$\frac{1}{\sqrt{4}} = \sqrt{0.25}$ $\frac{1}{\sqrt{32}} = \sqrt{0.0313}$6 $\frac{1}{\sqrt{2}} = \sqrt{0.5}$$\frac{1}{\sqrt{64}} = \sqrt{0.0156}$ 7 1 0

TABLE 2 SB amplitude codebook table Index SB amplitude (P_(2,l,i))(I_(A,SB)) Alt 0 Alt 1 0 $\frac{1}{\sqrt{2}} = \sqrt{0.5}$ 1 1 1$\frac{1}{\sqrt{2}} = \sqrt{0.5}$

In some embodiments 3F, for both wideband only and wideband+subbandamplitude quantization (depending on RRC configuration, cf. theaforementioned embodiments 3B), amplitude quantization is independentfor each of the remaining 2L−1 coefficients and for each layer. Thecodebook for amplitude quantization is as follows.

In one example of WB amplitude codebook, C_(WB)={1, √{square root over(0.6683)}, √{square root over (0.4467)}, √{square root over (0.2985)},√{square root over (0.1995)}, √{square root over (0.1334)}, √{squareroot over (0.0891)}, 0} which corresponds to ={0, −1.75, −3.5, . . . ,−10.5, −∞} dB. An example of WB amplitude codebook table is shown inTABLE 3. Two alternatives are shown for indexing, one in increasing andthe other in decreasing order of amplitudes, one of them may be fixed.

In another example of SB amplitude codebook, C_(SB)={√{square root over(1.4125)}, √{square root over (0.7079)}} for the first group (for whichN_(2,l,i)=1), which corresponds to ={1.5, −1.5} dB, and C_(SB)={1} forthe second group (for which N_(2,l,i)=0, SB amplitude is not reported).An example of SB amplitude codebook table is shown in TABLE 4. Twoalternatives are shown for indexing, one in increasing and the other indecreasing order of amplitudes, one of them may fixed in aspecification. In a variation, there is no separate codebook for SBamplitude. The SB amplitude codebook corresponds to indices I_(A,WB)=6,7 (Alt 0) or 0, 1 (Alt 1) in the WB amplitude codebook table TABLE 3.

TABLE 3 WB amplitude codebook table Index WB amplitude (p_(1,l,i))(I_(A,WB)) Alt 0 Alt 1 0 0 1 1 {square root over (0.0891)} {square rootover (0.6683)} 2 {square root over (0.1334)} {square root over (0.4467)}3 {square root over (0.1995)} {square root over (0.2985)} 4 {square rootover (0.2985)} {square root over (0.1995)} 5 {square root over (0.4467)}{square root over (0.1334)} 6 {square root over (0.6683)} {square rootover (0.0891)} 7 1 0

TABLE 4 SB amplitude codebook table Index SB amplitude (p_(2,l,i))(I_(A,SB)) Alt 0 Alt 1 0 {square root over (0.7079)} {square root over(1.4125)} 1 {square root over (1.4125)} {square root over (0.7079)}

In some embodiments 3G, the WB amplitude codebook is according to one ofAlt 0 and Alt 1 in TABLE 1 and the SB amplitude codebook is according toone of Alt 0 and Alt 1 in TABLE 4.

In some embodiments 3H, the WB amplitude codebook is according to one ofAlt 0 and Alt 1 in TABLE 3 and the SB amplitude codebook is according toone of Alt 0 and Alt 1 in TABLE 2.

In some embodiments 3I, the WB amplitude codebook is according to one ofAlt 0 and Alt 1 in TABLE 1 and the SB amplitude codebook is according toone of Alt 0 and Alt 1 in TABLE 5.

TABLE 5 SB amplitude codebook table Index SB amplitude (p_(2,l,i))(I_(A,SB)) Alt 0 Alt 1 0 {square root over (1.4125)} 1 1 1 {square rootover (1.4125)}

In some embodiments, the WB amplitude codebook is according to one ofAlt 0 and Alt 1 in TABLE 1 and the SB amplitude codebook is according toone of Alt 0 and Alt 1 in TABLE 6.

TABLE 6 SB amplitude codebook table Index SB amplitude (p_(2,l,i))(IA,sn) Alt 0 Alt 1 0 {square root over (0.7079)} 1 1 1 {square rootover (0.7079)}

In some embodiments 3K, the WB amplitude codebook is according to one ofAlt 0 and Alt 1 in TABLE 1 and two SB amplitude codebooks are supported,{1, √{square root over (x₁)}} and {1, √{square root over (x₂)}}, wherex₁>1 and x₂<1. In one example, the two SB codebooks are {1, √{squareroot over (1.4125)}} and {1, √{square root over (0.7079)}} and thecorresponding SB codebook table is shown in TABLE 7. Another example isshown in TABLE 8. In both tables, two alternatives (Alt 0 and Alt 1) ofindex (I_(A,SB)) of SB amplitude (p_(2,l,i)) mapping is shown.

The reporting or configuration of SB Codebook Index (I_(SB CB)) areaccording to at least one of the following alternatives. In one exampleof Alt 3K-0, one of the two SB codebooks is fixed in the specification,for example, {1, √{square root over (0.7079)}}. In another example ofAlt 3K-1, one of the two SB codebooks is configured to the UE. Forexample, this configuration can be via 1-bit RRC sign baling or moredynamic MAC CE based or DCI based signaling.

In yet another example of Alt 3K-2, the UE reports one of the two SBcodebooks as part of the CSI report where this reporting is in a WBmanner. Also, this reporting can either be joint with at least one ofother WB CSI reports (for example WB PMI or RI) or separate as a new WBCSI report. The WB reporting of I_(SB CB) is according to at least oneof the following sub-alternatives.

In one instance of Alt 3K-2-0, I_(SB CB) is reported layer-common andcoefficient-common and a 1-bit WB CSI report is reported common for alllayers and common for all coefficients (K−1), where K is defined as inthe aforementioned embodiments 3B.

In another instance of Alt 3K-2-1, I_(SB CB) is reported layer-commonand coefficient-independent and a 1-bit WB CSI report is reported commonfor all layers and independently for all coefficients (K−1), where K isdefined as in the aforementioned embodiments 3B. So, the total number ofWB reporting bits is K−1.

In yet another instance of Alt 3K-2-2, I_(SB CB) is reportedlayer-independent and coefficient-common and a 1-bit WB CSI report isreported independently for all layers and common for all coefficients(K−1), where K is defined as in the aforementioned embodiments 3B. So,the total number of WB reporting bits is R, where R is the number oflayers, (1 and 2 for rank 1 and rank 2, respectively).

In yet another instance of Alt 3K-2-3, I_(SB CB) is reportedlayer-independent and coefficient-independent and a 1-bit WB CSI reportis reported independently for all layers and independently for allcoefficients (K−1), where K is defined as in the aforementionedembodiments 3B. So, the total number of WB reporting bits is R(K−1),where R is the number of layers, and hence for rank 1 and rank 2, thenumber of bits is (K−1) and 2(K−1), respectively.

TABLE 7 SB amplitude codebook table SB Codebook Index Index SB amplitude(p_(2,l,i)) (I_(SB CB)) (I_(A,SB)) Alt 0 Alt 1 0 0 {square root over(1.4125)} 1 1 1 {square root over (1.4125)} 1 0 {square root over(0.7079)} 1 1 1 {square root over (0.7079)}

TABLE 8 SB amplitude codebook table SB Codebook Index Index SB amplitude(p_(2,l,i)) (I_(SB CB)) (I_(A,SB)) Alt 0 Alt 1 0 0 {square root over(0.7079)} 1 1 1 {square root over (0.7079)} 1 0 {square root over(1.4125)} 1 1 1 {square root over (1.4125)}

The WB and SB amplitude quantization codebooks according to only one ofthe aforementioned embodiments 3E, 3F, 3G, 3H, 3I, 3J, and 3K will bespecified in the present disclosure.

In some embodiments 3L, for 4 antenna ports (e.g. {3000, 3001, 3002,3003}), 8 antenna ports (e.g. {3000, 3001, . . . , 3007}), 12 antennaports (e.g. {3000, 3001, . . . , 3011}), 16 antenna ports (e.g. {3000,3001, . . . , 3015}), 24 antenna ports (e.g. {13000, 3001, . . . ,3023}), and 32 antenna ports (e.g. {3000, 3001, . . . , 3031}), when theUE is configured with higher layer parameters CodebookType set toType2_Parameters, where Type2_Parameters contains parameters{CodebookConfig-N1, CodebookConfig-N2, NumberOfBeams, PhaseAlphabetSize,SubbandAmplitude}.

In such embodiments, the values of N₁ and N₂ are configured with thehigher-layer parameters CodebookConfig-N1 and CodebookConfig-N2,respectively. The number of CSI-RS ports, P_(CSI-RS), is 2N₁N₂. In suchembodiments, the value of L is configured with the higher-layerparameter NumberOfBeams, where L=2 when P_(CSI-RS)=4 and L∈{2,3,4} whenP_(CSI-RS)>4. In such embodiments, the value of N_(PSK) is configuredwith the higher-layer parameter PhaseAlphabetSize, where N_(PSK)∈(4,8)with N_(PSK)=4 indicates QPSK phase codebook and N_(PSK)=8 indicates8PSK phase codebook. In such embodiments, the UE is configured with thehigher-layer parameter SubbandAmplitude set to OFF or ON.

When υ≤2, where υ is the associated RI value, each PMI value correspondsto the codebook indices i₁ and i₂ where

$i_{1} = \left\{ {{\begin{matrix}\left\lbrack {i_{1,1}\mspace{14mu} i_{1,2}\mspace{14mu} i_{1,3,1}\mspace{14mu} i_{1,4,1}} \right\rbrack & {v = 1} \\\left\lbrack {i_{1,1}\mspace{14mu} i_{1,2}\mspace{14mu} i_{1,3,1}\mspace{14mu} i_{1,4,1}\mspace{14mu} i_{1,3,2}\mspace{14mu} i_{1,4,2}} \right\rbrack & {v = 2}\end{matrix}\mspace{14mu}{and}i_{2}} = \left\{ {\begin{matrix}\left\lbrack i_{2,1,1} \right\rbrack & {{{SubandAmplitude}\  = {OFF}},\ {v = 1}} \\\left\lbrack {i_{2,1,1}\ i_{2,1,2}} \right\rbrack & {{{SubandAmplitude}\  = {OFF}},\ {v = 2}} \\\left\lbrack {i_{2,1,1}\ i_{2,2,1}} \right\rbrack & {{{SubandAmplitude}\  = {ON}},\ {v = 1}} \\\left\lbrack {i_{2,1,1}\ i_{2,2,1}\ i_{2,1,2}\ i_{2,2,2}} \right\rbrack & {{{SubandAmplitude}\  = {ON}},\ {v = 2}}\end{matrix}.} \right.} \right.$

The L vectors combined by the codebook are identified by the indicesi_(1,1) and i_(1,2), where

$\begin{matrix}{i_{1,1} = \left\lbrack {q_{1}\mspace{14mu} q_{2}} \right\rbrack} \\{q_{1} \in \left\{ {0,1,\ldots\mspace{11mu},{O_{1} - 1}} \right\}} \\{q_{2} \in \left\{ {0,1,\ldots\mspace{11mu},{O_{2} - 1}} \right\}}\end{matrix}\mspace{14mu}{and}\mspace{14mu}{\begin{matrix}{i_{1,2} = \left\lbrack {n_{1}\mspace{14mu} n_{2}} \right\rbrack} \\{n_{1} = \left\lbrack {n_{1}^{(0)},\ldots\mspace{11mu},n_{1}^{({L - 1})}} \right\rbrack} \\{n_{2} = \left\lbrack {n_{2}^{(0)}\mspace{14mu},\ldots\mspace{11mu},n_{2}^{({L - 1})}} \right\rbrack} \\{n_{1}^{(i)} \in \left\{ {0,1,\ldots\mspace{11mu},{N_{1} - 1}} \right\}} \\{n_{2}^{(i)} \in \left\{ {0,1,\ldots\mspace{11mu},{N_{2} - 1}} \right\}}\end{matrix}.}$

The strongest coefficient on layer l,l=1, . . . , υ is identified byi_(1,3,l)∈{0, 1, . . . , 2L−1}. The amplitude coefficient indicatorsi_(1,4,l) and i_(2,2,l) are

i_(1, 4, l) = [k_(l, 0)⁽¹⁾, k_(l, 1)⁽¹⁾, …  , k_(l, 2L − 1)⁽¹⁾]i_(2, 2, l) = [k_(l, 0)⁽²⁾, k_(l, 1)⁽²⁾, …  , k_(l, 2L − 1)⁽²⁾]k_(l, i)⁽¹⁾ ∈ {0, 1, …  , 7} k_(l, i)⁽²⁾ ∈ {0, 1}for l=1, . . . , υ.

The indicators i_(1,4,l) and i_(2,2,l) respectively indicate the WB andSB components of the coefficient amplitudes as explained earlier in thedisclosure. The mapping from k_(l,i) ⁽¹⁾ to the WB amplitude coefficientp_(l,i) ⁽¹⁾ is given in TABLE 9 and the mapping from k_(l,i) ⁽²⁾ to theSB amplitude coefficient p_(l,i) ⁽²⁾ is given in TABLE 10.

The amplitude coefficients are represented by

p_(l)⁽¹⁾ = [p_(l, 0)⁽¹⁾, p_(l, 1)⁽¹⁾, …  , p_(l, 2L − 1)⁽¹⁾]p_(l)⁽²⁾ = [p_(l, 0)⁽²⁾, p_(l, 1)⁽²⁾, …  , p_(l, 2L − 1)⁽²⁾]for l=1, . . . , υ. Note that p_(l,i) ⁽¹⁾ and p_(l,i) ⁽²⁾ respectivelyone-to-one map to p_(1,l,i) p_(2,l,i) and used earlier (or later) in thedisclosure for the WB and SB amplitude components.

TABLE 9 Mapping of elements of i_(1,4,l): k_(l,i) ⁽¹⁾ to p_(l,i) ⁽¹⁾k_(l,i) ⁽¹⁾ p_(l,i) ⁽¹⁾ 0 0 1 {square root over (1/64)} 2 {square rootover (1/32)} 3 {square root over (1/16)} 4 {square root over (1/8)} 5{square root over (1/4)} 6 {square root over (1/2)} 7 1

TABLE 10 Mapping of elements of i_(2,2,l): k_(l,i) ⁽²⁾ to p_(l,i) ⁽²⁾k_(l,i) ⁽²⁾ p_(l,i) ⁽²⁾ 0 {square root over (1/2)} 1 1

The phase coefficient indicators are i_(2,1,l)=c_(l)=[c_(l,0), c_(l,1),. . . , c_(l,2L−1)] for l=1, . . . , υ. The amplitude and phasecoefficient indicators are reported as follows. In one example, theindicators k_(l,i) _(1,3,l) ⁽¹⁾=7, k_(l,i) _(1,3,l) ⁽²⁾=1, and c_(l,i)_(1,3,l) =0 (l=1, . . . , υ). k_(l,i) _(1,3,l) ⁽¹⁾, k_(l,i) _(1,3,l)⁽²⁾, c_(l,i) _(1,3,l) and are not reported for l=1, . . . , υ.

In another example, the remaining 2L−1 elements of i_(1,4,1) (l=1, . . ., υ) are reported, where k_(l,i) ⁽¹⁾∈{0, 1, . . . , 7}. Let M_(l) (l=1,. . . υ) be the number of elements of i_(1,4,1) that satisfy k_(l,i)⁽¹⁾>0.

In yet another example, the remaining 2L−1 elements of i_(2,1,l) andi_(2,2,l) (l=1, . . . , υ) are reported as follows. In one instance,when SubbandAmplitude=OFF: k_(l,i) ⁽²⁾=1 for l=1, . . . , υ and i=0, 1,. . . , 2L−1. i_(2,2,l) is not reported for l=1, . . . , υ; and for l=1,. . . , υ, the M_(l)−1 elements of i_(2,1,l) corresponding to thecoefficients that satisfy k_(l,i) ⁽¹⁾>0, as determined by the reportedelements of i_(1,4,1), are reported, where c_(l,i)∈{0, 1, . . . ,N_(PSK)−1}, and the remaining 2L−M₁ elements of i_(2,1,l) are notreported and are set to c_(l,i)=0.

In another instance, when SubbandAmplitude=ON: for l=1, . . . , υ, theelements of i_(2,2,l) and i_(2,1,l) corresponding to the min(M_(l),K⁽²⁾)−1 strongest coefficients, as determined by the correspondingelements of i_(1,4,l), are reported, where k_(l,i) ⁽²⁾∈{0,1} andc_(l,j)∈{0, 1, . . . , N_(PSK)−1}. The values of K⁽²⁾ are given in TABLE11. The remaining 2L−min(M_(l),K⁽²⁾) elements of i_(2,2,l) are notreported and are set to k_(l,i) ⁽²⁾=1. The elements of i_(2,1,l)corresponding to the remaining M_(l)−min (M_(l), K⁽²⁾) coefficientssatisfying k_(l,i) ⁽¹⁾>0 are reported, where c_(l,i)∈{0, 1, 2, 3}. Theremaining 2L−M_(l) elements of i_(2,1,l) are not reported and are set toc_(l,i)=0; and when two elements, k_(l,x) ⁽¹⁾ and k_(l,y) ⁽¹⁾, of thereported i_(1,4,1) are identical (k_(l,x) ⁽¹⁾=k_(l,y) ⁽¹⁾), then theelement min(x, y) is prioritized to be included in the set of the min(M_(l),K⁽²⁾)−1 strongest coefficients for i_(2,2,l) and i_(2,1,l) (l=1,. . . , υ) reporting. In another alternative, max(x,y) is prioritized tobe included in the set of the min(M_(l),K⁽²⁾)−1 strongest coefficientsfor i_(2,2,l) and i_(2,1,l) (l=1, . . . , υ) reporting.

TABLE 11 Full resolution subband coefficients when SubbandAmplitude = ONL K⁽²⁾ 2 4 3 4 4 6

The phase coefficient is determined by the quantity

$\phi_{l,i} = \left\{ {\begin{matrix}{e^{{j2}\;\pi\; c_{l,i}}/N_{PSK}} & {{{Subband}Amplitude} = {OFF}} \\{e^{j\; 2\;\pi\; c_{l,i}}/N_{PSK}} & {{{{Subband}Amplitude} = {ON}},{{\min\left( {M_{l},K^{(2)}} \right)} - {1\mspace{14mu}{stronger}\mspace{14mu}{coefficients}}}} \\{e^{j\; 2\;\pi\; c_{l,i}}/4} & {{{{Subband}Amplitude} = {ON}},{M_{l} - {{\min\left( {M_{l},K^{(2)}} \right)}\mspace{14mu}{weaker}\mspace{14mu}{coefficients}}}}\end{matrix}.} \right.$

In some embodiments 3M, for 4 antenna ports (e.g. {3000, 3001, 3002,3003}), 8 antenna ports (e.g. {3000, 3001, . . . , 3007}), 12 antennaports (e.g. {3000, 3001, . . . , 3011}), 16 antenna ports (e.g. {3000,3001, . . . , 3015}), 24 antenna ports (e.g. {13000, 3001, . . . ,3023}), and 32 antenna ports (e.g. {3000, 3001, . . . , 3031}), when theUE is configured with higher layer parameters CodebookType set toType2_Parameters, where Type2_Parameters contains parameters{CodebookConfig-N1, CodebookConfig-N2, NumberOfBeams, PhaseAlphabetSize,SubbandAmplitude, PortSelectionSamplingSize}.

In such embodiments, the number of CSI-RS ports is given byP_(CSI-RS)∈{4,8,12,16,24,32}. In such embodiments, the value of L isconfigured with the higher-layer parameter NumberOfBeams, where L=2 whenP_(CSI-RS)=4 and L∈{2, 3, 4} when P_(CSI-RS)>4. In such embodiments, thevalue of d is configured with the higher layer parameterPortSelectionSamplingSize, where d∈{1, 2, 3, 4},

${d \leq {\frac{P_{{CSI} - {RS}}}{2}\mspace{14mu}{and}\mspace{14mu} d} \leq L},$alternatively

$d \leq {{\min\left( {\frac{P_{{CSI}\text{-}{RS}}}{2},L} \right)}.}$In such embodiments, the value of N_(PSK) is configured with thehigher-layer parameter PhaseAlphabetSize, where N_(PSK)∈(4,8) withN_(PSK)=4 indicates QPSK phase codebook and N_(PSK)=8 indicates 8PSKphase codebook. In such embodiments, the UE is configured with thehigher-layer parameter SubbandAmplitude set to OFF or ON.

When υ≥2, where υ is the associated RI value, each PMI value correspondsto the codebook indices i₁ and i₂ where

$i_{1} = \left\{ {{\begin{matrix}\left\lbrack {i_{1,1}\mspace{14mu} i_{1,3,1}\mspace{14mu} i_{1,4,1}} \right\rbrack & {v = 1} \\\left\lbrack {i_{1,1}\mspace{14mu} i_{1,3,1}\mspace{14mu} i_{1,4,1}\mspace{14mu} i_{1,3,2}\mspace{14mu} i_{1,4,2}} \right\rbrack & {v = 2}\end{matrix}\mspace{14mu}{and}i_{2}} = \left\{ {\begin{matrix}\left\lbrack i_{2,1,1} \right\rbrack & {{{SubandAmplitude}\  = {OFF}},\ {v = 1}} \\\left\lbrack {i_{2,1,1}\ i_{2,1,2}} \right\rbrack & {{{SubandAmplitude}\  = {OFF}},\ {v = 2}} \\\left\lbrack {i_{2,1,1}\ i_{2,2,1}} \right\rbrack & {{{SubandAmplitude}\  = {ON}},\ {v = 1}} \\\left\lbrack {i_{2,1,1}\ i_{2,2,1}\ i_{2,1,2}\ i_{2,2,2}} \right\rbrack & {{{SubandAmplitude}\  = {ON}},\ {v = 2}}\end{matrix}.} \right.} \right.$

The L antenna ports per polarization are selected by the index i_(1,1),where

$i_{1,1} \in {\left\{ {0,1,\ldots\mspace{14mu},{\left\lceil \frac{P_{{CSI} - {RS}}}{2d} \right\rceil - 1}} \right\}.}$The rest of the details are the same as in the aforementionedembodiments (e.g., embodiment 3L).

In some embodiments 4, for Alt 1-0 or Alt 1-1 of amplitude sorting, thebit allocation is common for each of L beams across two polarizations:for L=2 beams and max 2 bits/amplitude, the bit allocation is accordingto at least one alternative in TABLE 12; for L=2 beams and max 3bits/amplitude, the bit allocation is according to at least onealternative in TABLE 13; for L=3 beams and max 2 bits/amplitude, the bitallocation is according to at least one alternative in TABLE 14; for L=3beams and max 3 bits/amplitude, the bit allocation is according to atleast one alternative in TABLE 15; for L=4 beams and max 2bits/amplitude, the bit allocation is according to at least onealternative in TABLE 16; and for L=4 beams and max 3 bits/amplitude, thebit allocation is according to at least one alternative in TABLE 17.

Note that if the number of bit N_(1,l,i)=0, then the amplitude is equalto 1 (strongest beam) and if N_(1,l,i)>0, then the amplitude codebook isas in the aforementioned embodiment 0. In these alternatives, thestrongest beam is common for both of the two polarizations (i=0 and L),hence the corresponding amplitudes are not reported (assumed to be 1).

The UE is configured with an L value belonging to {2, 3, 4} and a maxnumber of bits/amplitude value belonging to {2, 3}. This configurationis via higher layer RRC signaling. In another alternative, the UEreports a preferred L value (WB report) and a max number ofbits/amplitude value belonging to {2, 3} is configured via RRCsignaling.

In one embodiment, only one of the alternatives in TABLES 12-17 issupported in the present disclosure. In another embodiment, the UE isconfigured with one of the bit allocation alternatives in TABLES 12-17via higher layer RRC or more dynamic MAC CE based or DCI basedsignaling. In yet another embodiment, the UE reports a preferred bitallocation as part of the CSI report where this reporting is WB eitherjointly with at least one of other WB CSI reports or separately asanother WB CSI report.

TABLE 12 Bit allocation for L = 2 and max 2 bits/amplitude, commonquantization bits across polarization Amplitude index i Bit allocation(after sorting) Number of bits Alt0 0, 2 N_(1,l,0) = N_(1,l,2) 0 1, 3N_(1,l,1) = N_(1,l,3) 2

TABLE 13 Bit allocation for L = 2 and max 3 bits/amplitude, commonquantization bits across polarization Amplitude index i Bit allocation(after sorting) Number of bits Alt0 0, 2 N_(1,l,0) = N_(1,l,2) 0 1, 3N_(1,l,1) = N_(1,l,3) 3

TABLE 14 Bit allocation for L = 3 and max 2 bits/amplitude, commonquantization bits across polarization Amplitude index i Bit allocation(after sorting) Number of bits Alt0 Alt1 Alt2 0, 3 N_(1,l,0) = N_(1,l,3)0 0 0 1, 4 N_(1,l,1) = N_(1,l,4) 2 2 2 2, 5 N_(1,l,2) = N_(1,l,5) 2 1 0

TABLE 15 Bit allocation for L = 3 and max 3 bits/amplitude, commonquantization bits across polarization Amplitude index i Bit allocation(after sorting) Number of bits Alt0 Alt1 Alt2 Alt3 0, 3 N_(1,l,0) =N_(1,l,3) 0 0 0 0 1, 4 N_(1,l,1) = N_(1,l,4) 3 3 3 3 2, 5 N_(1,l,2) =N_(1,l,5) 3 2 1 0

TABLE 16 Bit allocation for L = 4 and max 2 bits/amplitude, commonquantization bits across polarization Amplitude index i Number Bitallocation (after sorting) of bits Alt0 Alt1 Alt2 Alt3 Alt4 Alt5 0, 4N_(1,l,0) = N_(1,l,4) 0 0 0 0 0 0 1, 5 N_(1,l,1) = N_(1,l,5) 2 2 2 2 2 22, 6 N_(1,l,2) = N_(1,l,6) 2 2 2 1 1 0 3, 7 N_(1,l,3) = N_(1,l,7) 2 1 01 0 0

TABLE 17 Bit allocation for L = 4 and max 3 bits/amplitude, commonquantization bits across polarization Amplitude Number index i of Bitallocation (after sorting) bits Alt0 Alt1 Alt2 Alt3 Alt4 Alt5 Alt6 Alt7Alt8 Alt9 0, 4 N_(1,l,0) = N_(1,l,4) 0 0 0 0 0 0 0 0 0 0 1, 5 N_(1,l,1)= N_(1,l,5) 3 3 3 3 3 3 3 3 3 3 2, 6 N_(1,l,2) = N_(1,l,6) 3 3 3 2 3 2 21 1 0 3, 7 N_(1,l,3) = N_(1,l,7) 3 2 1 2 0 1 0 1 0 0

In some embodiments, for Alt 1-0 or Alt 1-1 of amplitude sorting, thebit allocation is common for each of L beams across two polarizations:for L=2 beams and max 2 bits/amplitude, the bit allocation is accordingto at least one alternative in TABLE 18; for L=2 beams and max 3bits/amplitude, the bit allocation is according to at least onealternative in TABLE 19; for L=3 beams and max 2 bits/amplitude, the bitallocation is according to at least one alternative in TABLE 20; for L=3beams and max 3 bits/amplitude, the bit allocation is according to atleast one alternative in TABLE 21; for L=4 beams and max 2bits/amplitude, the bit allocation is according to at least onealternative in TABLE 22; and for L=4 beams and max 3 bits/amplitude, thebit allocation is according to at least one alternative in TABLE 23.

Note that if the number of bit N_(1,l,i)=0, then the amplitude is equalto 1 and if N_(1,l,i)>0, then the amplitude codebook is as in theaforementioned embodiment 0. In these alternatives, the strongest beamcorresponds to one of the two polarizations (i=0), hence thecorresponding amplitude is not reported (assumed to be 1), and theamplitude corresponding to the other polarization (i=L) is reported.

The UE is configured with an L value belonging to {2, 3, 4} and a maxnumber of bits/amplitude value belonging to {2, 3}. This configurationis via higher layer RRC signaling. In another alternative, the UEreports a preferred L value (WB report) and a max number ofbits/amplitude value belonging to {2, 3} is configured via RRCsignaling.

In one embodiment, only one of the alternatives in TABLES 18-23 issupported in the specification. In another method, the UE is configuredwith one of the bit allocation alternatives in TABLES 18-23 via higherlayer RRC or more dynamic MAC CE based or DCI based signaling. In yetanother alternative, the UE reports a preferred bit allocation as partof the CSI report where this reporting is WB either jointly with atleast one of other WB CSI reports or separately as another WB CSIreport.

TABLE 18 Bit allocation for L = 2 and max 2 bits/amplitude, commonquantization bits across polarization Amplitude index i Bit allocation(after sorting) Number of bits Alt0 Alt1 Alt2 0 N_(1,l,0) 0 0 0 2N_(1,l,2) 2 2 2 1, 3 N_(1,l,1) = N_(1,l,3) 2 1 0

TABLE 19 Bit allocation for L = 2 and max 3 bits/amplitude, commonquantization bits across polarization Amplitude index i Bit allocation(after sorting) Number of bits Alt0 Alt1 Alt2 Alt3 0 N_(1,l,0) 0 0 0 0 2N_(1,l,2) 3 3 3 3 1, 3 N_(1,l,1) = N_(1,l,3) 3 2 1 0

TABLE 20 Bit allocation for L = 3 and max 2 bits/amplitude, commonquantization bits across polarization Amplitude index i Number Bitallocation (after sorting) of bits Alt0 Alt1 Alt2 Alt3 Alt4 Alt5 0N_(1,l,0) 0 0 0 0 0 0 3 N_(1,l,3) 2 2 2 2 2 2 1, 4 N_(1,l,1) = N_(1,l,4)2 2 2 1 1 0 2, 5 N_(1,l,2) = N_(1,l,5) 2 1 0 1 0 0

TABLE 21 Bit allocation for L = 3 and max 3 bits/amplitude, commonquantization bits across polarization Amplitude index i Number Bitallocation (after sorting) of bits Alt0 Alt1 Alt2 Alt3 Alt4 Alt5 Alt6Alt7 Alt8 Alt9 0 N_(1,l,0) 0 0 0 0 0 0 0 0 0 0 3 N_(1,l,3) 3 3 3 3 3 3 33 3 3 1, 4 N_(1,l,1) = N_(1,l,4) 3 3 3 2 3 2 2 1 1 0 2, 5 N_(1,l,2) =N_(1,l,5) 3 2 1 2 0 1 0 1 0 0

TABLE 22 Bit allocation for L = 4 and max 2 bits/amplitude, commonquantization bits across polarization Amplitude index i Number Bitallocation (after sorting) of bits Alt0 Alt1 Alt2 Alt3 Alt4 Alt5 Alt6Alt7 Alt8 0 N_(1,l,0) 0 0 0 0 0 0 0 0 0 4 N_(1,l,4) 2 2 2 2 2 2 2 2 2 1,5 N_(1,l,1) = N_(1,l,5) 2 2 2 2 2 2 1 1 0 2, 6 N_(1,l,2) = N_(1,l,6) 2 22 1 1 0 1 0 0 3, 7 N_(1,l,3) = N_(1,l,7) 2 1 0 1 0 0 0 0 0

TABLE 23 Bit allocation for L = 4 and max 3 bits/amplitude, commonquantization bits across polarization Amplitude index i Number Bitallocation (after sorting) of bits Alt0 Alt1 Alt2 Alt3 Alt4 Alt5 Alt6Alt7 0 N_(1,1,0) 0 0 0 0 0 0 0 0 4 N_(1,1,4) 3 3 3 3 3 3 3 3 1, 5N_(1,1,1) = N_(1,1,5) 3 3 3 3 3 3 3 3 2, 6 N_(1,1,2) = N_(1,1,6) 3 3 3 23 2 2 1 3, 7 N_(1,1,3) = N_(1,1,7) 3 2 1 2 0 1 0 1 Amplitude index iNumber Bit allocation (after sorting) of bits Alt8 Alt9 Alt10 Alt11Alt12 Alt13 Alt14 Alt15 0 N_(1,l,0) 0 0 0 0 0 0 0 0 4 N_(1,l,4) 3 3 3 33 3 3 3 1, 5 N_(1,l,1) = N_(1,l,5) 3 2 3 2 2 1 1 0 2, 6 N_(1,l,2) =N_(1,l,6) 1 2 0 1 0 1 0 0 3, 7 N_(1,l,3) = N_(1,l,7) 0 0 0 0 0 0 0 0

In some embodiments 6, for Alt 1-2 or Alt 1-3 of amplitude sorting, thebit allocation is independent for each of L beams and two polarizations:for L=2 beams and max 2 bits/amplitude, the bit allocation is accordingto at least one alternative in TABLE 24; for L=2 beams and max 3bits/amplitude, the bit allocation is according to at least onealternative in TABLE 25; for L=3 beams and max 2 bits/amplitude, the bitallocation is according to at least one alternative in TABLE 26; for L=3beams and max 3 bits/amplitude, the bit allocation is according to atleast one alternative in TABLE 27; for L=4 beams and max 2bits/amplitude, the bit allocation is according to at least onealternative in TABLE 28; and for L=4 beams and max 3 bits/amplitude, thebit allocation is according to at least one alternative in TABLE 29.

Note that if the number of bit N_(1,l,i)=0, then the amplitude is equalto 1 and if N_(1,l,i)>0, then the amplitude codebook is as in theaforementioned embodiments 0. In these alternatives, the strongest beamcorresponds to one of the two polarizations (i=0), hence thecorresponding amplitude is not reported (assumed to be 1), and theamplitude corresponding to the other polarization (i=L) is reported. Theamplitudes for remaining 2L−2 coefficients are reported independently.

The UE is configured with an L value belonging to {2, 3, 4} and a maxnumber of bits/amplitude value belonging to {2, 3}. This configurationis via higher layer RRC signaling. In another alternative, the UEreports a preferred L value (WB report) and a max number ofbits/amplitude value belonging to {2, 3} is configured via RRCsignaling.

In one embodiment, only one of the alternatives in TABLES 24-29 issupported in the specification. In another embodiment, the UE isconfigured with one of the bit allocation alternatives in TABLE 24-29via higher layer RRC or more dynamic MAC CE based or DCI basedsignaling. In yet another alternative, the UE reports a preferred bitallocation as part of the CSI report where this reporting is WB eitherjointly with at least one of other WB CSI reports or separately asanother WB CSI report.

TABLE 24 Bit allocation for L = 2 and max 2 bits/amplitude, independentquantization across polarization Amplitude index i Number Bit allocation(after sorting) of bits Alt0 Alt1 Alt2 Alt3 Alt4 Alt5 0 N_(1,l,0) 0 0 00 0 0 1 N_(1,l,1) 2 2 2 2 2 2 2 N_(1,l,2) 2 2 2 1 1 0 3 N_(1,l,3) 2 1 01 0 0

TABLE 25 Bit allocation for L = 2 and max 3 bits/amplitude, independentquantization across polarization Amplitude index i Number Bit allocation(after sorting) of bits Alt0 Alt1 Alt2 Alt3 Alt4 Alt5 Alt6 Alt7 Alt8Alt9 0 N_(1,l,0) 0 0 0 0 0 0 0 0 0 0 1 N_(1,l,1) 3 3 3 3 3 3 3 3 3 3 2N_(1,l,2) 3 3 3 2 3 2 2 1 1 0 3 N_(1,l,3) 3 2 1 2 0 1 0 1 0 0

TABLE 26 Bit allocation for L = 3 and max 2 bits/amplitude, independentquantization across polarization Amplitude index i Number Bit allocation(after sorting) of bits Alt0 Alt1 Alt2 Alt3 Alt4 Alt5 Alt6 Alt7 Alt8Alt9 Alt10 Alt11 0 N_(1,l,0) 0 0 0 0 0 0 0 0 0 0 0 0 1 N_(1,l,1) 2 2 2 22 2 2 2 2 2 2 2 2 N_(1,l,2) 2 2 2 2 2 2 2 2 2 1 1 0 3 N_(1,l,3) 2 2 2 22 2 1 1 0 1 0 0 4 N_(1,l,4) 2 2 2 1 1 0 1 0 0 0 0 0 5 N_(1,l,5) 2 1 0 10 0 0 0 0 0 0 0

TABLE 27 Bit allocation for L = 3 and max 3 bits/amplitude, independentquantization across polarization Amplitude index i Number Bit allocation(after sorting) of bits Alt0 Alt1 Alt2 Alt3 Alt4 Alt5 Alt6 Alt7 Alt8Alt9 Alt10 0 N_(1,l,0) 0 0 0 0 0 0 0 0 0 0 0 1 N_(1,l,1) 3 3 3 3 3 3 3 33 3 3 2 N_(1,l,2) 3 3 3 3 3 3 3 3 3 3 3 3 N_(1,l,3) 3 3 3 3 3 3 3 3 3 23 4 N_(1,l,4) 3 3 3 2 3 2 2 1 1 2 0 5 N_(1,l,5) 3 2 1 2 0 1 0 1 0 0 0Amplitude index i Number Bit allocation (after sorting) of bits Alt11Alt12 Alt13 Alt14 Alt15 Alt16 Alt17 Alt18 Alt19 Alt20 Alt21 0 N_(1,l,0)0 0 0 0 0 0 0 0 0 0 0 1 N_(1,l,1) 3 3 3 3 3 3 3 3 3 3 3 2 N_(1,l,2) 3 33 3 2 3 2 2 1 1 0 3 N_(1,l,3) 2 2 1 1 2 0 1 0 1 0 0 4 N_(1,l,4) 1 0 1 00 0 0 0 0 0 0 5 N_(1,l,5) 0 0 0 0 0 0 0 0 0 0 0

TABLE 28 Bit allocation for L = 4 and max 2 bits/amplitude, independentquantization across polarization Amplitude index i Bit allocation(number of bits) (after sorting) Alt0 Alt1 Alt2 Alt3 Alt4 Alt5 Alt6 Alt7Alt8 0 0 0 0 0 0 0 0 0 0 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 3 2 2 22 2 2 2 2 2 4 2 2 2 2 2 2 2 2 2 5 2 2 2 2 2 2 1 1 0 6 2 2 2 1 1 0 1 0 07 2 1 0 1 0 0 0 0 0 Amplitude index i Bit allocation (number of bits)(after sorting) Alt9 Alt10 Alt11 Alt12 Alt13 Alt14 Alt15 Alt16 Alt17 0 00 0 0 0 0 0 0 0 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 1 1 0 3 2 2 2 1 1 0 10 0 4 1 1 0 1 0 0 0 0 0 5 1 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 0 7 0 0 00 0 0 0 0 0

TABLE 29 Bit allocation for L = 4 and max 3 bits/amplitude, independentquantization across polarization Amplitude index i Bit allocation(number of bits) (after sorting) Alt0 Alt1 Alt2 Alt3 Alt4 Alt5 Alt6 Alt7Alt8 Alt9 Alt10 Alt11 0 0 0 0 0 0 0 0 0 0 0 0 0 1 3 3 3 3 3 3 3 3 3 3 33 2 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 4 3 3 3 3 3 3 3 33 3 3 3 5 3 3 3 3 3 3 3 3 3 2 3 2 6 3 3 3 2 3 2 2 1 1 2 0 1 7 3 2 1 2 01 0 1 0 0 0 0 Amplitude index i Bit allocation (number of bits) (aftersorting) Alt12 Alt13 Alt14 Alt15 Alt16 Alt17 Alt18 Alt19 Alt20 Alt21Alt22 Alt23 0 0 0 0 0 0 0 0 0 0 0 0 0 1 3 3 3 3 3 3 3 3 3 3 3 3 2 3 3 33 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 2 3 2 4 3 3 3 2 3 2 2 1 1 2 0 1 52 1 1 2 0 1 0 1 0 0 0 0 6 0 1 0 0 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 0 00 0 Amplitude index i Bit allocation (number of bits) (after sorting)Alt24 Alt25 Alt25 Alt26 Alt27 Alt28 Alt29 Alt30 Alt31 Alt32 0 0 0 0 0 00 0 0 0 0 1 3 3 3 3 3 3 3 3 3 3 2 3 3 3 2 3 2 2 1 1 0 3 2 1 1 2 0 1 0 10 0 4 0 1 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 0 0 70 0 0 0 0 0 0 0 0 0

In some embodiments 7, the bit-allocation for phase is according to atleast one of the following. In one example of Alt 7-0, thebit-allocation for phase is the same as that for amplitude and isaccording to at least one of the bit allocation alternatives in theaforementioned embodiments 4-6. In another example of Alt 7-1, thebit-allocation for phase is different from that for amplitude and isaccording to at least one of the bit allocation alternatives in theaforementioned embodiments 4-6. In yet another example of Alt 7-2, thebit allocation of phase is fixed, for example to equal bit allocation to2 or 3 bits.

In some embodiments 8, a UE is configured (via RRC signaling) with an Lvalue belonging to {2, 3, 4}, a max number of bits/amplitude valuebelonging to {2, 3}, and the total of amplitude quantization bitsΣ_(i=0) ^(2L−1) N_(1,l,i) or/and Σ_(i=0) ^(2L−1) N_(2,l,i). The UEreports the quantized amplitudes according to one of the bit allocationalternatives in the aforementioned embodiments 4-6. If there are morethan one bit allocation alternatives that satisfy the configured valueof the total of amplitude quantization bits, then the UE reports apreferred bit allocation out of all such bit allocation alternativeswhere this reporting is WB either jointly with other WB CSI reports orseparately as another WB CSI report.

In some embodiments 9, a UE is configured with bit allocation foramplitude or/and phase reporting according to at least one of thefollowing alternatives. In one instance of Alt 9-0, the bit allocationis equal for all L. In one instance of Alt 9-1, the bit allocation isunequal for all L values. In one instance of Alt 9-2, the bit allocationis equal or unequal for all L values depending on configuration. In oneinstance of Alt 9-3, the bit allocation is equal for L≤M and is unequalfor L>M. An example value for M is 2. Another example value for M is 3.

FIG. 13 illustrates a flowchart of a method 1300 for PMI reportingaccording to embodiments of the present disclosure. The method 1300 maybe performed by a UE, for example, UE 116, according to embodiments ofthe present disclosure. The embodiment of the method 1300 illustrated inFIG. 13 is for illustration only. FIG. 13 does not limit the scope ofthis disclosure to any particular implementation.

The method 1300 begins with the UE generating a report for a PMI (step1305). In step 1305, the report includes, at least, (i) a widebandamplitude coefficient indicator that is common for a plurality ofsubbands configured for reporting and (ii) a subband amplitudecoefficient indicator and a subband phase coefficient indicator for eachof the subbands. In some embodiments, the report includes 2*L number ofbeam coefficients for each of the subbands and for each of a pluralityof υ layers where L is a number of beams configured for reporting and υis a RI value associated with the reported PMI. Each of one or more ofthe beam coefficients includes (i) the wideband amplitude coefficientindicator that is common for the subbands and (ii) the subband amplitudecoefficient indicator and the subband phase coefficient indicator foreach of the subbands. Additionally, at least one of the beamcoefficients is reported using a number of bits that is unequal tonumber of bits used to report another of the beam coefficients.

In various embodiments, the UE includes in the report, for each of the υlayers, a strongest of the 2*L number of beam coefficients that iscommon for the subbands and groups the remaining 2*L−1 number of beamcoefficients into two groups. In these embodiments, a fewer number ofbits are used to report the beam coefficients in a second of the twogroups; hence, an unequal number of bits to report the two groups. In atleast some of these embodiments, a first of the two groups includesmin(M,K)−1 beam coefficients that are strongest coefficients of theremaining 2*L−1 number of beam coefficients and the second groupincludes 2L−min(M,K) beam coefficients where M is a number of beamcoefficients whose wideband amplitude coefficient indicators indicatenon-zero wideband amplitude values and K is a positive integer. In theseembodiments, the report does not include subband amplitude coefficientindicators for the second group of beam coefficients. In someembodiments, the strongest coefficients used to group the remaining2*L−1 beam coefficients into the two groups are determined based on thewideband amplitude coefficient indicator for each of the beamcoefficients.

In various embodiments, for each beam coefficient in the first group, 3bits are used to report the wideband amplitude coefficient indicator; 1bit is used to report the subband amplitude coefficient indicator; and 2or 3 bits are configured to report the subband phase coefficientindicator. For the second group, for each beam coefficient, 3 bits areused to report the wideband amplitude coefficient indicator; for eachbeam coefficient in the M−min(M,K) beam coefficients whose widebandamplitude coefficient indicators indicate non-zero wideband amplitudevalues, 2 bits are used to report the subband phase coefficientindicator; and for the remaining 2L−M beam coefficients whose widebandamplitude coefficient indicators indicate a zero wideband amplitudevalue, subband phase coefficient indicators are not reported.

Thereafter, the UE transmits the generated report for the PMI to a BS(step 1310). In step 1310, the UE reports the PMI to the BS, forexample, BS 102.

Although the present disclosure has been described with an exemplaryembodiment, various changes and modifications may be suggested to oneskilled in the art. It is intended that the present disclosure encompasssuch changes and modifications as fall within the scope of the appendedclaims.

None of the description in this application should be read as implyingthat any particular element, step, or function is an essential elementthat must be included in the claims scope. The scope of patented subjectmatter is defined only by the claims. Moreover, none of the claims areintended to invoke 35 U.S.C. § 112(f) unless the exact words “means for”are followed by a participle.

What is claimed is:
 1. A terminal for transmitting a signal in awireless communication system, the terminal comprising: a transceiverconfigured to transmit and receive a signal; and a controller coupledwith the transceiver and configured to: receive, from a base station, amessage including information configuring a codebook for a precodingmatrix indicator (PMI), generate channel state information (CSI)including the PMI based on the information, and transmit, to the basestation, the CSI including the PMI, wherein a bit size for a subbandamplitude associated with the PMI is 0, in case that the informationconfigures that a subband amplitude is not reported, and wherein the bitsize for the subband amplitude associated with the PMI is related to avalue (K) identified based on a number of beams (L), in case that theinformation configures that the subband amplitude is reported.
 2. Theterminal of claim 1, wherein the value (K) is identified as 4 in casethat the number of beams (L) is 2 or 3, and the value (K) is identifiedas 6 in case that the number of beams (L) is
 4. 3. The terminal of claim1, wherein a bit size for a wideband amplitude associated with the PMIis related to a number of 2L−1 coefficients, where L is the number ofbeams, and wherein a bit size for a subband phase associated with thePMI is independently identified for each case of the informationconfigures that the subband amplitude is not reported and theinformation configures that the subband amplitude is reported.
 4. Theterminal of claim 3, wherein in case of the information configures thatthe subband amplitude is reported, 2L−1 coefficients are partitionedinto group 1 comprising a first number of coefficients, and group 2comprising a second number of coefficients, wherein the first number ofcoefficients and the second number of coefficients are related to thevalue (K) identified based on the number of beams (L), and coefficientsin group 1 and coefficients in group 2 are determined based on thewideband amplitude for each of the 2L−1 coefficients such that group 1includes strongest of the 2L−1 coefficients having larger widebandamplitude values.
 5. The terminal of claim 4, wherein a number of bitsfor a subband phase corresponding to each of the first number ofcoefficients is 2 or 3, and the number of bits for the subband phasecorresponding to each of a second number of coefficients is 2, in casethat the information configures that the subband amplitude is reported.6. The terminal of claim 4, wherein in case of the informationconfigures that the subband amplitude is reported, the subband amplitudeis reported for each coefficient in group 1, and wherein a subbandamplitude corresponding to coefficients in group 2 is not reported. 7.The terminal of claim 3, wherein a number of bits for the widebandamplitude corresponding to each of the coefficients is 3, wherein anumber of bits for the subband amplitude corresponding to each of thecoefficients in group 1 is 1, and wherein a number of bits for thesubband amplitude corresponding to each of the coefficients in group 2is
 0. 8. A base station for receiving a signal in a wirelesscommunication system, the base station comprising: a transceiverconfigured to transmit and receive a signal; and a controller coupledwith the transceiver and configured to: transmit, to a terminal, amessage including information configuring a codebook for a precodingmatrix indicator (PMI), and receive, from the terminal, channel stateinformation (CSI) including the PMI and generated based on theinformation, wherein a bit size for a subband amplitude associated withthe PMI is 0, in case that the information configures that a subbandamplitude is not reported, and wherein the bit size for the subbandamplitude associated with the PMI is related to a value (K) identifiedbased on a number of beams (L), in case that the information configuresthat the subband amplitude is reported.
 9. The base station of claim 8,wherein the value (K) is identified as 4 in case that the number ofbeams (L) is 2 or 3, and the value (K) is identified as 6 in case thatthe number of beams (L) is
 4. 10. The base station of claim 8, wherein abit size for a wideband amplitude associated with the PMI is related toa number of 2L−1 coefficients, where L is the number of beams, andwherein a bit size for a subband phase associated with the PMI isindependently identified for each case of the information configuresthat the subband amplitude is not reported and the informationconfigures that the subband amplitude is reported.
 11. The base stationof claim 10, wherein, in case of the information configures that thesubband amplitude is reported, 2L−1 coefficients are partitioned intogroup 1 comprising a first number of coefficients, and group 2comprising a second number of coefficients, wherein the first number ofcoefficients and the second number of coefficients are related to thevalue (K) identified based on the number of beams (L), and coefficientsin group 1 and coefficients in group 2 are determined based on thewideband amplitude for each of the 2L−1 coefficients such that group 1includes strongest of the 2L−1 coefficients having larger widebandamplitude values.
 12. The base station of claim 11, wherein a number ofbits for a subband phase corresponding to each of the first number ofcoefficients is 2 or 3, and the number of bits for the subband phasecorresponding to each of a second number of coefficients is 2, in casethat the information configures that the subband amplitude is reported.13. The base station of claim 11, wherein in case of the informationconfigures that the subband amplitude is reported, the subband amplitudeis reported for each coefficient in group 1, and wherein a subbandamplitude corresponding to coefficients in group 2 is not reported. 14.The base station of claim 10, wherein a number of bits for the widebandamplitude corresponding to each of plurality of coefficients is 3,wherein a number of bits for the subband amplitude corresponding to eachof the coefficients in group 1 is 1, and wherein a number of bits forthe subband amplitude corresponding to each of the coefficients in group2 is
 0. 15. A method of transmitting a signal by a terminal in awireless communication system, the method comprising: receiving, from abase station, a message including information configuring a codebook fora precoding matrix indicator (PMI); generating channel state information(CSI) including the PMI based on the information; and transmitting, tothe base station, the CSI including the PMI, wherein a bit size for asubband amplitude associated with the PMI is 0, in case that theinformation configures that a subband amplitude is not reported, andwherein the bit size for the subband amplitude associated with the PMIis related to a value (K) identified based on a number of beams (L), incase that the information configures that the subband amplitude isreported.
 16. The method of claim 15, wherein the value (K) isidentified as 4 in case that the number of beams (L) is 2 or 3, and thevalue (K) is identified as 6 in case that the number of beams (L) is 4.17. The method of claim 15, wherein a bit size for a wideband amplitudeassociated with the PMI is related to a number of 2L−1 coefficients,where L is the number of beams, and wherein a bit size for a subbandphase associated with the PMI is independently identified for each caseof the information configures that the subband amplitude is not reportedand the information configures that the subband amplitude is reported.18. The method of claim 17, wherein in case of the informationconfigures that the subband amplitude is reported, 2L−1 coefficients arepartitioned into group 1 comprising a first number of coefficients, andgroup 2 comprising a second number of coefficients, wherein the firstnumber of coefficients and the second number of coefficients are relatedto the value (K) identified based on the number of beams (L), andcoefficients in group 1 and coefficients in group 2 are determined basedon the wideband amplitude for each of the 2L−1 coefficients such thatgroup 1 includes strongest of the 2L−1 coefficients having largerwideband amplitude values.
 19. The method of claim 18, wherein a numberof bits for a subband phase corresponding to each of the first number ofcoefficients is 2 or 3, and the number of bits for the subband phasecorresponding to each of a second number of coefficients is 2, in casethat the information configures that the subband amplitude is reported.20. The method of claim 18, wherein in case of the informationconfigures that the subband amplitude is reported, the subband amplitudeis reported for each coefficient in group 1, and wherein a subbandamplitude corresponding to coefficients in group 2 is not reported.